diff --git a/packages/google-cloud-translate/package.json b/packages/google-cloud-translate/package.json
index 3a0ab0a1831..c5199f99978 100644
--- a/packages/google-cloud-translate/package.json
+++ b/packages/google-cloud-translate/package.json
@@ -52,7 +52,7 @@
     "@google-cloud/promisify": "^2.0.0",
     "arrify": "^2.0.0",
     "extend": "^3.0.2",
-    "google-gax": "^2.1.0",
+    "google-gax": "^2.9.2",
     "is-html": "^2.0.0",
     "protobufjs": "^6.8.8"
   },
diff --git a/packages/google-cloud-translate/src/index.ts b/packages/google-cloud-translate/src/index.ts
index 807b96497d1..58aff8bcf7e 100644
--- a/packages/google-cloud-translate/src/index.ts
+++ b/packages/google-cloud-translate/src/index.ts
@@ -57,6 +57,7 @@ import * as v3 from './v3';
 export * from './v3';
 
 const TranslationServiceClient = v3.TranslationServiceClient;
+type TranslationServiceClient = v3.TranslationServiceClient;
 export {TranslationServiceClient, v2, v3beta1, v3};
 // For compatibility with JavaScript libraries we need to provide this default export:
 // tslint:disable-next-line no-default-export
diff --git a/packages/google-cloud-translate/src/v3/translation_service_client.ts b/packages/google-cloud-translate/src/v3/translation_service_client.ts
index e5f517496bf..01c61964eb3 100644
--- a/packages/google-cloud-translate/src/v3/translation_service_client.ts
+++ b/packages/google-cloud-translate/src/v3/translation_service_client.ts
@@ -62,8 +62,10 @@ export class TranslationServiceClient {
   /**
    * Construct an instance of TranslationServiceClient.
    *
-   * @param {object} [options] - The configuration object. See the subsequent
-   *   parameters for more details.
+   * @param {object} [options] - The configuration object.
+   * The options accepted by the constructor are described in detail
+   * in [this document](https://github.com/googleapis/gax-nodejs/blob/master/client-libraries.md#creating-the-client-instance).
+   * The common options are:
    * @param {object} [options.credentials] - Credentials object.
    * @param {string} [options.credentials.client_email]
    * @param {string} [options.credentials.private_key]
@@ -83,42 +85,33 @@ export class TranslationServiceClient {
    *     your project ID will be detected automatically.
    * @param {string} [options.apiEndpoint] - The domain name of the
    *     API remote host.
+   * @param {gax.ClientConfig} [options.clientConfig] - client configuration override.
+   *     TODO(@alexander-fenster): link to gax documentation.
+   * @param {boolean} fallback - Use HTTP fallback mode.
+   *     In fallback mode, a special browser-compatible transport implementation is used
+   *     instead of gRPC transport. In browser context (if the `window` object is defined)
+   *     the fallback mode is enabled automatically; set `options.fallback` to `false`
+   *     if you need to override this behavior.
    */
-
   constructor(opts?: ClientOptions) {
-    // Ensure that options include the service address and port.
+    // Ensure that options include all the required fields.
     const staticMembers = this.constructor as typeof TranslationServiceClient;
     const servicePath =
-      opts && opts.servicePath
-        ? opts.servicePath
-        : opts && opts.apiEndpoint
-        ? opts.apiEndpoint
-        : staticMembers.servicePath;
-    const port = opts && opts.port ? opts.port : staticMembers.port;
+      opts?.servicePath || opts?.apiEndpoint || staticMembers.servicePath;
+    const port = opts?.port || staticMembers.port;
+    const clientConfig = opts?.clientConfig ?? {};
+    const fallback = opts?.fallback ?? typeof window !== 'undefined';
+    opts = Object.assign({servicePath, port, clientConfig, fallback}, opts);
 
-    if (!opts) {
-      opts = {servicePath, port};
+    // If scopes are unset in options and we're connecting to a non-default endpoint, set scopes just in case.
+    if (servicePath !== staticMembers.servicePath && !('scopes' in opts)) {
+      opts['scopes'] = staticMembers.scopes;
     }
-    opts.servicePath = opts.servicePath || servicePath;
-    opts.port = opts.port || port;
-
-    // users can override the config from client side, like retry codes name.
-    // The detailed structure of the clientConfig can be found here: https://github.com/googleapis/gax-nodejs/blob/master/src/gax.ts#L546
-    // The way to override client config for Showcase API:
-    //
-    // const customConfig = {"interfaces": {"google.showcase.v1beta1.Echo": {"methods": {"Echo": {"retry_codes_name": "idempotent", "retry_params_name": "default"}}}}}
-    // const showcaseClient = new showcaseClient({ projectId, customConfig });
-    opts.clientConfig = opts.clientConfig || {};
 
-    // If we're running in browser, it's OK to omit `fallback` since
-    // google-gax has `browser` field in its `package.json`.
-    // For Electron (which does not respect `browser` field),
-    // pass `{fallback: true}` to the TranslationServiceClient constructor.
+    // Choose either gRPC or proto-over-HTTP implementation of google-gax.
     this._gaxModule = opts.fallback ? gax.fallback : gax;
 
-    // Create a `gaxGrpc` object, with any grpc-specific options
-    // sent to the client.
-    opts.scopes = (this.constructor as typeof TranslationServiceClient).scopes;
+    // Create a `gaxGrpc` object, with any grpc-specific options sent to the client.
     this._gaxGrpc = new this._gaxModule.GrpcClient(opts);
 
     // Save options to use in initialize() method.
@@ -127,6 +120,11 @@ export class TranslationServiceClient {
     // Save the auth object to the client, for use by other methods.
     this.auth = this._gaxGrpc.auth as gax.GoogleAuth;
 
+    // Set the default scopes in auth client if needed.
+    if (servicePath === staticMembers.servicePath) {
+      this.auth.defaultScopes = staticMembers.scopes;
+    }
+
     // Determine the client header string.
     const clientHeader = [`gax/${this._gaxModule.version}`, `gapic/${version}`];
     if (typeof process !== 'undefined' && 'versions' in process) {
@@ -321,6 +319,7 @@ export class TranslationServiceClient {
 
   /**
    * The DNS address for this API service.
+   * @returns {string} The DNS address for this service.
    */
   static get servicePath() {
     return 'translate.googleapis.com';
@@ -329,6 +328,7 @@ export class TranslationServiceClient {
   /**
    * The DNS address for this API service - same as servicePath(),
    * exists for compatibility reasons.
+   * @returns {string} The DNS address for this service.
    */
   static get apiEndpoint() {
     return 'translate.googleapis.com';
@@ -336,6 +336,7 @@ export class TranslationServiceClient {
 
   /**
    * The port for this API service.
+   * @returns {number} The default port for this service.
    */
   static get port() {
     return 443;
@@ -344,6 +345,7 @@ export class TranslationServiceClient {
   /**
    * The scopes needed to make gRPC calls for every method defined
    * in this service.
+   * @returns {string[]} List of default scopes.
    */
   static get scopes() {
     return [
@@ -356,8 +358,7 @@ export class TranslationServiceClient {
   getProjectId(callback: Callback<string, undefined, undefined>): void;
   /**
    * Return the project ID used by this class.
-   * @param {function(Error, string)} callback - the callback to
-   *   be called with the current project Id.
+   * @returns {Promise} A promise that resolves to string containing the project ID.
    */
   getProjectId(
     callback?: Callback<string, undefined, undefined>
@@ -474,7 +475,11 @@ export class TranslationServiceClient {
    *   Call options. See {@link https://googleapis.dev/nodejs/google-gax/latest/interfaces/CallOptions.html|CallOptions} for more details.
    * @returns {Promise} - The promise which resolves to an array.
    *   The first element of the array is an object representing [TranslateTextResponse]{@link google.cloud.translation.v3.TranslateTextResponse}.
-   *   The promise has a method named "cancel" which cancels the ongoing API call.
+   *   Please see the
+   *   [documentation](https://github.com/googleapis/gax-nodejs/blob/master/client-libraries.md#regular-methods)
+   *   for more details and examples.
+   * @example
+   * const [response] = await client.translateText(request);
    */
   translateText(
     request: protos.google.cloud.translation.v3.ITranslateTextRequest,
@@ -596,7 +601,11 @@ export class TranslationServiceClient {
    *   Call options. See {@link https://googleapis.dev/nodejs/google-gax/latest/interfaces/CallOptions.html|CallOptions} for more details.
    * @returns {Promise} - The promise which resolves to an array.
    *   The first element of the array is an object representing [DetectLanguageResponse]{@link google.cloud.translation.v3.DetectLanguageResponse}.
-   *   The promise has a method named "cancel" which cancels the ongoing API call.
+   *   Please see the
+   *   [documentation](https://github.com/googleapis/gax-nodejs/blob/master/client-libraries.md#regular-methods)
+   *   for more details and examples.
+   * @example
+   * const [response] = await client.detectLanguage(request);
    */
   detectLanguage(
     request: protos.google.cloud.translation.v3.IDetectLanguageRequest,
@@ -718,7 +727,11 @@ export class TranslationServiceClient {
    *   Call options. See {@link https://googleapis.dev/nodejs/google-gax/latest/interfaces/CallOptions.html|CallOptions} for more details.
    * @returns {Promise} - The promise which resolves to an array.
    *   The first element of the array is an object representing [SupportedLanguages]{@link google.cloud.translation.v3.SupportedLanguages}.
-   *   The promise has a method named "cancel" which cancels the ongoing API call.
+   *   Please see the
+   *   [documentation](https://github.com/googleapis/gax-nodejs/blob/master/client-libraries.md#regular-methods)
+   *   for more details and examples.
+   * @example
+   * const [response] = await client.getSupportedLanguages(request);
    */
   getSupportedLanguages(
     request: protos.google.cloud.translation.v3.IGetSupportedLanguagesRequest,
@@ -806,7 +819,11 @@ export class TranslationServiceClient {
    *   Call options. See {@link https://googleapis.dev/nodejs/google-gax/latest/interfaces/CallOptions.html|CallOptions} for more details.
    * @returns {Promise} - The promise which resolves to an array.
    *   The first element of the array is an object representing [Glossary]{@link google.cloud.translation.v3.Glossary}.
-   *   The promise has a method named "cancel" which cancels the ongoing API call.
+   *   Please see the
+   *   [documentation](https://github.com/googleapis/gax-nodejs/blob/master/client-libraries.md#regular-methods)
+   *   for more details and examples.
+   * @example
+   * const [response] = await client.getGlossary(request);
    */
   getGlossary(
     request: protos.google.cloud.translation.v3.IGetGlossaryRequest,
@@ -953,8 +970,15 @@ export class TranslationServiceClient {
    * @param {object} [options]
    *   Call options. See {@link https://googleapis.dev/nodejs/google-gax/latest/interfaces/CallOptions.html|CallOptions} for more details.
    * @returns {Promise} - The promise which resolves to an array.
-   *   The first element of the array is an object representing [Operation]{@link google.longrunning.Operation}.
-   *   The promise has a method named "cancel" which cancels the ongoing API call.
+   *   The first element of the array is an object representing
+   *   a long running operation. Its `promise()` method returns a promise
+   *   you can `await` for.
+   *   Please see the
+   *   [documentation](https://github.com/googleapis/gax-nodejs/blob/master/client-libraries.md#long-running-operations)
+   *   for more details and examples.
+   * @example
+   * const [operation] = await client.batchTranslateText(request);
+   * const [response] = await operation.promise();
    */
   batchTranslateText(
     request: protos.google.cloud.translation.v3.IBatchTranslateTextRequest,
@@ -1006,18 +1030,19 @@ export class TranslationServiceClient {
     return this.innerApiCalls.batchTranslateText(request, options, callback);
   }
   /**
-   * Check the status of the long running operation returned by the batchTranslateText() method.
+   * Check the status of the long running operation returned by `batchTranslateText()`.
    * @param {String} name
    *   The operation name that will be passed.
    * @returns {Promise} - The promise which resolves to an object.
    *   The decoded operation object has result and metadata field to get information from.
-   *
-   * @example:
-   *   const decodedOperation = await checkBatchTranslateTextProgress(name);
-   *   console.log(decodedOperation.result);
-   *   console.log(decodedOperation.done);
-   *   console.log(decodedOperation.metadata);
-   *
+   *   Please see the
+   *   [documentation](https://github.com/googleapis/gax-nodejs/blob/master/client-libraries.md#long-running-operations)
+   *   for more details and examples.
+   * @example
+   * const decodedOperation = await checkBatchTranslateTextProgress(name);
+   * console.log(decodedOperation.result);
+   * console.log(decodedOperation.done);
+   * console.log(decodedOperation.metadata);
    */
   async checkBatchTranslateTextProgress(
     name: string
@@ -1090,8 +1115,15 @@ export class TranslationServiceClient {
    * @param {object} [options]
    *   Call options. See {@link https://googleapis.dev/nodejs/google-gax/latest/interfaces/CallOptions.html|CallOptions} for more details.
    * @returns {Promise} - The promise which resolves to an array.
-   *   The first element of the array is an object representing [Operation]{@link google.longrunning.Operation}.
-   *   The promise has a method named "cancel" which cancels the ongoing API call.
+   *   The first element of the array is an object representing
+   *   a long running operation. Its `promise()` method returns a promise
+   *   you can `await` for.
+   *   Please see the
+   *   [documentation](https://github.com/googleapis/gax-nodejs/blob/master/client-libraries.md#long-running-operations)
+   *   for more details and examples.
+   * @example
+   * const [operation] = await client.createGlossary(request);
+   * const [response] = await operation.promise();
    */
   createGlossary(
     request: protos.google.cloud.translation.v3.ICreateGlossaryRequest,
@@ -1143,18 +1175,19 @@ export class TranslationServiceClient {
     return this.innerApiCalls.createGlossary(request, options, callback);
   }
   /**
-   * Check the status of the long running operation returned by the createGlossary() method.
+   * Check the status of the long running operation returned by `createGlossary()`.
    * @param {String} name
    *   The operation name that will be passed.
    * @returns {Promise} - The promise which resolves to an object.
    *   The decoded operation object has result and metadata field to get information from.
-   *
-   * @example:
-   *   const decodedOperation = await checkCreateGlossaryProgress(name);
-   *   console.log(decodedOperation.result);
-   *   console.log(decodedOperation.done);
-   *   console.log(decodedOperation.metadata);
-   *
+   *   Please see the
+   *   [documentation](https://github.com/googleapis/gax-nodejs/blob/master/client-libraries.md#long-running-operations)
+   *   for more details and examples.
+   * @example
+   * const decodedOperation = await checkCreateGlossaryProgress(name);
+   * console.log(decodedOperation.result);
+   * console.log(decodedOperation.done);
+   * console.log(decodedOperation.metadata);
    */
   async checkCreateGlossaryProgress(
     name: string
@@ -1226,8 +1259,15 @@ export class TranslationServiceClient {
    * @param {object} [options]
    *   Call options. See {@link https://googleapis.dev/nodejs/google-gax/latest/interfaces/CallOptions.html|CallOptions} for more details.
    * @returns {Promise} - The promise which resolves to an array.
-   *   The first element of the array is an object representing [Operation]{@link google.longrunning.Operation}.
-   *   The promise has a method named "cancel" which cancels the ongoing API call.
+   *   The first element of the array is an object representing
+   *   a long running operation. Its `promise()` method returns a promise
+   *   you can `await` for.
+   *   Please see the
+   *   [documentation](https://github.com/googleapis/gax-nodejs/blob/master/client-libraries.md#long-running-operations)
+   *   for more details and examples.
+   * @example
+   * const [operation] = await client.deleteGlossary(request);
+   * const [response] = await operation.promise();
    */
   deleteGlossary(
     request: protos.google.cloud.translation.v3.IDeleteGlossaryRequest,
@@ -1279,18 +1319,19 @@ export class TranslationServiceClient {
     return this.innerApiCalls.deleteGlossary(request, options, callback);
   }
   /**
-   * Check the status of the long running operation returned by the deleteGlossary() method.
+   * Check the status of the long running operation returned by `deleteGlossary()`.
    * @param {String} name
    *   The operation name that will be passed.
    * @returns {Promise} - The promise which resolves to an object.
    *   The decoded operation object has result and metadata field to get information from.
-   *
-   * @example:
-   *   const decodedOperation = await checkDeleteGlossaryProgress(name);
-   *   console.log(decodedOperation.result);
-   *   console.log(decodedOperation.done);
-   *   console.log(decodedOperation.metadata);
-   *
+   *   Please see the
+   *   [documentation](https://github.com/googleapis/gax-nodejs/blob/master/client-libraries.md#long-running-operations)
+   *   for more details and examples.
+   * @example
+   * const decodedOperation = await checkDeleteGlossaryProgress(name);
+   * console.log(decodedOperation.result);
+   * console.log(decodedOperation.done);
+   * console.log(decodedOperation.metadata);
    */
   async checkDeleteGlossaryProgress(
     name: string
@@ -1369,19 +1410,14 @@ export class TranslationServiceClient {
    *   Call options. See {@link https://googleapis.dev/nodejs/google-gax/latest/interfaces/CallOptions.html|CallOptions} for more details.
    * @returns {Promise} - The promise which resolves to an array.
    *   The first element of the array is Array of [Glossary]{@link google.cloud.translation.v3.Glossary}.
-   *   The client library support auto-pagination by default: it will call the API as many
+   *   The client library will perform auto-pagination by default: it will call the API as many
    *   times as needed and will merge results from all the pages into this array.
-   *
-   *   When autoPaginate: false is specified through options, the array has three elements.
-   *   The first element is Array of [Glossary]{@link google.cloud.translation.v3.Glossary} that corresponds to
-   *   the one page received from the API server.
-   *   If the second element is not null it contains the request object of type [ListGlossariesRequest]{@link google.cloud.translation.v3.ListGlossariesRequest}
-   *   that can be used to obtain the next page of the results.
-   *   If it is null, the next page does not exist.
-   *   The third element contains the raw response received from the API server. Its type is
-   *   [ListGlossariesResponse]{@link google.cloud.translation.v3.ListGlossariesResponse}.
-   *
-   *   The promise has a method named "cancel" which cancels the ongoing API call.
+   *   Note that it can affect your quota.
+   *   We recommend using `listGlossariesAsync()`
+   *   method described below for async iteration which you can stop as needed.
+   *   Please see the
+   *   [documentation](https://github.com/googleapis/gax-nodejs/blob/master/client-libraries.md#auto-pagination)
+   *   for more details and examples.
    */
   listGlossaries(
     request: protos.google.cloud.translation.v3.IListGlossariesRequest,
@@ -1429,18 +1465,7 @@ export class TranslationServiceClient {
   }
 
   /**
-   * Equivalent to {@link listGlossaries}, but returns a NodeJS Stream object.
-   *
-   * This fetches the paged responses for {@link listGlossaries} continuously
-   * and invokes the callback registered for 'data' event for each element in the
-   * responses.
-   *
-   * The returned object has 'end' method when no more elements are required.
-   *
-   * autoPaginate option will be ignored.
-   *
-   * @see {@link https://nodejs.org/api/stream.html}
-   *
+   * Equivalent to `method.name.toCamelCase()`, but returns a NodeJS Stream object.
    * @param {Object} request
    *   The request object that will be sent.
    * @param {string} request.parent
@@ -1461,6 +1486,13 @@ export class TranslationServiceClient {
    *   Call options. See {@link https://googleapis.dev/nodejs/google-gax/latest/interfaces/CallOptions.html|CallOptions} for more details.
    * @returns {Stream}
    *   An object stream which emits an object representing [Glossary]{@link google.cloud.translation.v3.Glossary} on 'data' event.
+   *   The client library will perform auto-pagination by default: it will call the API as many
+   *   times as needed. Note that it can affect your quota.
+   *   We recommend using `listGlossariesAsync()`
+   *   method described below for async iteration which you can stop as needed.
+   *   Please see the
+   *   [documentation](https://github.com/googleapis/gax-nodejs/blob/master/client-libraries.md#auto-pagination)
+   *   for more details and examples.
    */
   listGlossariesStream(
     request?: protos.google.cloud.translation.v3.IListGlossariesRequest,
@@ -1485,10 +1517,9 @@ export class TranslationServiceClient {
   }
 
   /**
-   * Equivalent to {@link listGlossaries}, but returns an iterable object.
-   *
-   * for-await-of syntax is used with the iterable to recursively get response element on-demand.
+   * Equivalent to `listGlossaries`, but returns an iterable object.
    *
+   * `for`-`await`-`of` syntax is used with the iterable to get response elements on-demand.
    * @param {Object} request
    *   The request object that will be sent.
    * @param {string} request.parent
@@ -1508,7 +1539,18 @@ export class TranslationServiceClient {
    * @param {object} [options]
    *   Call options. See {@link https://googleapis.dev/nodejs/google-gax/latest/interfaces/CallOptions.html|CallOptions} for more details.
    * @returns {Object}
-   *   An iterable Object that conforms to @link https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols.
+   *   An iterable Object that allows [async iteration](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols).
+   *   When you iterate the returned iterable, each element will be an object representing
+   *   [Glossary]{@link google.cloud.translation.v3.Glossary}. The API will be called under the hood as needed, once per the page,
+   *   so you can stop the iteration when you don't need more results.
+   *   Please see the
+   *   [documentation](https://github.com/googleapis/gax-nodejs/blob/master/client-libraries.md#auto-pagination)
+   *   for more details and examples.
+   * @example
+   * const iterable = client.listGlossariesAsync(request);
+   * for await (const response of iterable) {
+   *   // process response
+   * }
    */
   listGlossariesAsync(
     request?: protos.google.cloud.translation.v3.IListGlossariesRequest,
@@ -1622,9 +1664,10 @@ export class TranslationServiceClient {
   }
 
   /**
-   * Terminate the GRPC channel and close the client.
+   * Terminate the gRPC channel and close the client.
    *
    * The client will no longer be usable and all future behavior is undefined.
+   * @returns {Promise} A promise that resolves when the client is closed.
    */
   close(): Promise<void> {
     this.initialize();
diff --git a/packages/google-cloud-translate/src/v3beta1/translation_service_client.ts b/packages/google-cloud-translate/src/v3beta1/translation_service_client.ts
index 37a583cec37..c077797bcac 100644
--- a/packages/google-cloud-translate/src/v3beta1/translation_service_client.ts
+++ b/packages/google-cloud-translate/src/v3beta1/translation_service_client.ts
@@ -62,8 +62,10 @@ export class TranslationServiceClient {
   /**
    * Construct an instance of TranslationServiceClient.
    *
-   * @param {object} [options] - The configuration object. See the subsequent
-   *   parameters for more details.
+   * @param {object} [options] - The configuration object.
+   * The options accepted by the constructor are described in detail
+   * in [this document](https://github.com/googleapis/gax-nodejs/blob/master/client-libraries.md#creating-the-client-instance).
+   * The common options are:
    * @param {object} [options.credentials] - Credentials object.
    * @param {string} [options.credentials.client_email]
    * @param {string} [options.credentials.private_key]
@@ -83,42 +85,33 @@ export class TranslationServiceClient {
    *     your project ID will be detected automatically.
    * @param {string} [options.apiEndpoint] - The domain name of the
    *     API remote host.
+   * @param {gax.ClientConfig} [options.clientConfig] - client configuration override.
+   *     TODO(@alexander-fenster): link to gax documentation.
+   * @param {boolean} fallback - Use HTTP fallback mode.
+   *     In fallback mode, a special browser-compatible transport implementation is used
+   *     instead of gRPC transport. In browser context (if the `window` object is defined)
+   *     the fallback mode is enabled automatically; set `options.fallback` to `false`
+   *     if you need to override this behavior.
    */
-
   constructor(opts?: ClientOptions) {
-    // Ensure that options include the service address and port.
+    // Ensure that options include all the required fields.
     const staticMembers = this.constructor as typeof TranslationServiceClient;
     const servicePath =
-      opts && opts.servicePath
-        ? opts.servicePath
-        : opts && opts.apiEndpoint
-        ? opts.apiEndpoint
-        : staticMembers.servicePath;
-    const port = opts && opts.port ? opts.port : staticMembers.port;
+      opts?.servicePath || opts?.apiEndpoint || staticMembers.servicePath;
+    const port = opts?.port || staticMembers.port;
+    const clientConfig = opts?.clientConfig ?? {};
+    const fallback = opts?.fallback ?? typeof window !== 'undefined';
+    opts = Object.assign({servicePath, port, clientConfig, fallback}, opts);
 
-    if (!opts) {
-      opts = {servicePath, port};
+    // If scopes are unset in options and we're connecting to a non-default endpoint, set scopes just in case.
+    if (servicePath !== staticMembers.servicePath && !('scopes' in opts)) {
+      opts['scopes'] = staticMembers.scopes;
     }
-    opts.servicePath = opts.servicePath || servicePath;
-    opts.port = opts.port || port;
-
-    // users can override the config from client side, like retry codes name.
-    // The detailed structure of the clientConfig can be found here: https://github.com/googleapis/gax-nodejs/blob/master/src/gax.ts#L546
-    // The way to override client config for Showcase API:
-    //
-    // const customConfig = {"interfaces": {"google.showcase.v1beta1.Echo": {"methods": {"Echo": {"retry_codes_name": "idempotent", "retry_params_name": "default"}}}}}
-    // const showcaseClient = new showcaseClient({ projectId, customConfig });
-    opts.clientConfig = opts.clientConfig || {};
 
-    // If we're running in browser, it's OK to omit `fallback` since
-    // google-gax has `browser` field in its `package.json`.
-    // For Electron (which does not respect `browser` field),
-    // pass `{fallback: true}` to the TranslationServiceClient constructor.
+    // Choose either gRPC or proto-over-HTTP implementation of google-gax.
     this._gaxModule = opts.fallback ? gax.fallback : gax;
 
-    // Create a `gaxGrpc` object, with any grpc-specific options
-    // sent to the client.
-    opts.scopes = (this.constructor as typeof TranslationServiceClient).scopes;
+    // Create a `gaxGrpc` object, with any grpc-specific options sent to the client.
     this._gaxGrpc = new this._gaxModule.GrpcClient(opts);
 
     // Save options to use in initialize() method.
@@ -127,6 +120,11 @@ export class TranslationServiceClient {
     // Save the auth object to the client, for use by other methods.
     this.auth = this._gaxGrpc.auth as gax.GoogleAuth;
 
+    // Set the default scopes in auth client if needed.
+    if (servicePath === staticMembers.servicePath) {
+      this.auth.defaultScopes = staticMembers.scopes;
+    }
+
     // Determine the client header string.
     const clientHeader = [`gax/${this._gaxModule.version}`, `gapic/${version}`];
     if (typeof process !== 'undefined' && 'versions' in process) {
@@ -322,6 +320,7 @@ export class TranslationServiceClient {
 
   /**
    * The DNS address for this API service.
+   * @returns {string} The DNS address for this service.
    */
   static get servicePath() {
     return 'translate.googleapis.com';
@@ -330,6 +329,7 @@ export class TranslationServiceClient {
   /**
    * The DNS address for this API service - same as servicePath(),
    * exists for compatibility reasons.
+   * @returns {string} The DNS address for this service.
    */
   static get apiEndpoint() {
     return 'translate.googleapis.com';
@@ -337,6 +337,7 @@ export class TranslationServiceClient {
 
   /**
    * The port for this API service.
+   * @returns {number} The default port for this service.
    */
   static get port() {
     return 443;
@@ -345,6 +346,7 @@ export class TranslationServiceClient {
   /**
    * The scopes needed to make gRPC calls for every method defined
    * in this service.
+   * @returns {string[]} List of default scopes.
    */
   static get scopes() {
     return [
@@ -357,8 +359,7 @@ export class TranslationServiceClient {
   getProjectId(callback: Callback<string, undefined, undefined>): void;
   /**
    * Return the project ID used by this class.
-   * @param {function(Error, string)} callback - the callback to
-   *   be called with the current project Id.
+   * @returns {Promise} A promise that resolves to string containing the project ID.
    */
   getProjectId(
     callback?: Callback<string, undefined, undefined>
@@ -475,7 +476,11 @@ export class TranslationServiceClient {
    *   Call options. See {@link https://googleapis.dev/nodejs/google-gax/latest/interfaces/CallOptions.html|CallOptions} for more details.
    * @returns {Promise} - The promise which resolves to an array.
    *   The first element of the array is an object representing [TranslateTextResponse]{@link google.cloud.translation.v3beta1.TranslateTextResponse}.
-   *   The promise has a method named "cancel" which cancels the ongoing API call.
+   *   Please see the
+   *   [documentation](https://github.com/googleapis/gax-nodejs/blob/master/client-libraries.md#regular-methods)
+   *   for more details and examples.
+   * @example
+   * const [response] = await client.translateText(request);
    */
   translateText(
     request: protos.google.cloud.translation.v3beta1.ITranslateTextRequest,
@@ -600,7 +605,11 @@ export class TranslationServiceClient {
    *   Call options. See {@link https://googleapis.dev/nodejs/google-gax/latest/interfaces/CallOptions.html|CallOptions} for more details.
    * @returns {Promise} - The promise which resolves to an array.
    *   The first element of the array is an object representing [DetectLanguageResponse]{@link google.cloud.translation.v3beta1.DetectLanguageResponse}.
-   *   The promise has a method named "cancel" which cancels the ongoing API call.
+   *   Please see the
+   *   [documentation](https://github.com/googleapis/gax-nodejs/blob/master/client-libraries.md#regular-methods)
+   *   for more details and examples.
+   * @example
+   * const [response] = await client.detectLanguage(request);
    */
   detectLanguage(
     request: protos.google.cloud.translation.v3beta1.IDetectLanguageRequest,
@@ -725,7 +734,11 @@ export class TranslationServiceClient {
    *   Call options. See {@link https://googleapis.dev/nodejs/google-gax/latest/interfaces/CallOptions.html|CallOptions} for more details.
    * @returns {Promise} - The promise which resolves to an array.
    *   The first element of the array is an object representing [SupportedLanguages]{@link google.cloud.translation.v3beta1.SupportedLanguages}.
-   *   The promise has a method named "cancel" which cancels the ongoing API call.
+   *   Please see the
+   *   [documentation](https://github.com/googleapis/gax-nodejs/blob/master/client-libraries.md#regular-methods)
+   *   for more details and examples.
+   * @example
+   * const [response] = await client.getSupportedLanguages(request);
    */
   getSupportedLanguages(
     request: protos.google.cloud.translation.v3beta1.IGetSupportedLanguagesRequest,
@@ -817,7 +830,11 @@ export class TranslationServiceClient {
    *   Call options. See {@link https://googleapis.dev/nodejs/google-gax/latest/interfaces/CallOptions.html|CallOptions} for more details.
    * @returns {Promise} - The promise which resolves to an array.
    *   The first element of the array is an object representing [Glossary]{@link google.cloud.translation.v3beta1.Glossary}.
-   *   The promise has a method named "cancel" which cancels the ongoing API call.
+   *   Please see the
+   *   [documentation](https://github.com/googleapis/gax-nodejs/blob/master/client-libraries.md#regular-methods)
+   *   for more details and examples.
+   * @example
+   * const [response] = await client.getGlossary(request);
    */
   getGlossary(
     request: protos.google.cloud.translation.v3beta1.IGetGlossaryRequest,
@@ -966,8 +983,15 @@ export class TranslationServiceClient {
    * @param {object} [options]
    *   Call options. See {@link https://googleapis.dev/nodejs/google-gax/latest/interfaces/CallOptions.html|CallOptions} for more details.
    * @returns {Promise} - The promise which resolves to an array.
-   *   The first element of the array is an object representing [Operation]{@link google.longrunning.Operation}.
-   *   The promise has a method named "cancel" which cancels the ongoing API call.
+   *   The first element of the array is an object representing
+   *   a long running operation. Its `promise()` method returns a promise
+   *   you can `await` for.
+   *   Please see the
+   *   [documentation](https://github.com/googleapis/gax-nodejs/blob/master/client-libraries.md#long-running-operations)
+   *   for more details and examples.
+   * @example
+   * const [operation] = await client.batchTranslateText(request);
+   * const [response] = await operation.promise();
    */
   batchTranslateText(
     request: protos.google.cloud.translation.v3beta1.IBatchTranslateTextRequest,
@@ -1019,18 +1043,19 @@ export class TranslationServiceClient {
     return this.innerApiCalls.batchTranslateText(request, options, callback);
   }
   /**
-   * Check the status of the long running operation returned by the batchTranslateText() method.
+   * Check the status of the long running operation returned by `batchTranslateText()`.
    * @param {String} name
    *   The operation name that will be passed.
    * @returns {Promise} - The promise which resolves to an object.
    *   The decoded operation object has result and metadata field to get information from.
-   *
-   * @example:
-   *   const decodedOperation = await checkBatchTranslateTextProgress(name);
-   *   console.log(decodedOperation.result);
-   *   console.log(decodedOperation.done);
-   *   console.log(decodedOperation.metadata);
-   *
+   *   Please see the
+   *   [documentation](https://github.com/googleapis/gax-nodejs/blob/master/client-libraries.md#long-running-operations)
+   *   for more details and examples.
+   * @example
+   * const decodedOperation = await checkBatchTranslateTextProgress(name);
+   * console.log(decodedOperation.result);
+   * console.log(decodedOperation.done);
+   * console.log(decodedOperation.metadata);
    */
   async checkBatchTranslateTextProgress(
     name: string
@@ -1103,8 +1128,15 @@ export class TranslationServiceClient {
    * @param {object} [options]
    *   Call options. See {@link https://googleapis.dev/nodejs/google-gax/latest/interfaces/CallOptions.html|CallOptions} for more details.
    * @returns {Promise} - The promise which resolves to an array.
-   *   The first element of the array is an object representing [Operation]{@link google.longrunning.Operation}.
-   *   The promise has a method named "cancel" which cancels the ongoing API call.
+   *   The first element of the array is an object representing
+   *   a long running operation. Its `promise()` method returns a promise
+   *   you can `await` for.
+   *   Please see the
+   *   [documentation](https://github.com/googleapis/gax-nodejs/blob/master/client-libraries.md#long-running-operations)
+   *   for more details and examples.
+   * @example
+   * const [operation] = await client.createGlossary(request);
+   * const [response] = await operation.promise();
    */
   createGlossary(
     request: protos.google.cloud.translation.v3beta1.ICreateGlossaryRequest,
@@ -1156,18 +1188,19 @@ export class TranslationServiceClient {
     return this.innerApiCalls.createGlossary(request, options, callback);
   }
   /**
-   * Check the status of the long running operation returned by the createGlossary() method.
+   * Check the status of the long running operation returned by `createGlossary()`.
    * @param {String} name
    *   The operation name that will be passed.
    * @returns {Promise} - The promise which resolves to an object.
    *   The decoded operation object has result and metadata field to get information from.
-   *
-   * @example:
-   *   const decodedOperation = await checkCreateGlossaryProgress(name);
-   *   console.log(decodedOperation.result);
-   *   console.log(decodedOperation.done);
-   *   console.log(decodedOperation.metadata);
-   *
+   *   Please see the
+   *   [documentation](https://github.com/googleapis/gax-nodejs/blob/master/client-libraries.md#long-running-operations)
+   *   for more details and examples.
+   * @example
+   * const decodedOperation = await checkCreateGlossaryProgress(name);
+   * console.log(decodedOperation.result);
+   * console.log(decodedOperation.done);
+   * console.log(decodedOperation.metadata);
    */
   async checkCreateGlossaryProgress(
     name: string
@@ -1239,8 +1272,15 @@ export class TranslationServiceClient {
    * @param {object} [options]
    *   Call options. See {@link https://googleapis.dev/nodejs/google-gax/latest/interfaces/CallOptions.html|CallOptions} for more details.
    * @returns {Promise} - The promise which resolves to an array.
-   *   The first element of the array is an object representing [Operation]{@link google.longrunning.Operation}.
-   *   The promise has a method named "cancel" which cancels the ongoing API call.
+   *   The first element of the array is an object representing
+   *   a long running operation. Its `promise()` method returns a promise
+   *   you can `await` for.
+   *   Please see the
+   *   [documentation](https://github.com/googleapis/gax-nodejs/blob/master/client-libraries.md#long-running-operations)
+   *   for more details and examples.
+   * @example
+   * const [operation] = await client.deleteGlossary(request);
+   * const [response] = await operation.promise();
    */
   deleteGlossary(
     request: protos.google.cloud.translation.v3beta1.IDeleteGlossaryRequest,
@@ -1292,18 +1332,19 @@ export class TranslationServiceClient {
     return this.innerApiCalls.deleteGlossary(request, options, callback);
   }
   /**
-   * Check the status of the long running operation returned by the deleteGlossary() method.
+   * Check the status of the long running operation returned by `deleteGlossary()`.
    * @param {String} name
    *   The operation name that will be passed.
    * @returns {Promise} - The promise which resolves to an object.
    *   The decoded operation object has result and metadata field to get information from.
-   *
-   * @example:
-   *   const decodedOperation = await checkDeleteGlossaryProgress(name);
-   *   console.log(decodedOperation.result);
-   *   console.log(decodedOperation.done);
-   *   console.log(decodedOperation.metadata);
-   *
+   *   Please see the
+   *   [documentation](https://github.com/googleapis/gax-nodejs/blob/master/client-libraries.md#long-running-operations)
+   *   for more details and examples.
+   * @example
+   * const decodedOperation = await checkDeleteGlossaryProgress(name);
+   * console.log(decodedOperation.result);
+   * console.log(decodedOperation.done);
+   * console.log(decodedOperation.metadata);
    */
   async checkDeleteGlossaryProgress(
     name: string
@@ -1382,19 +1423,14 @@ export class TranslationServiceClient {
    *   Call options. See {@link https://googleapis.dev/nodejs/google-gax/latest/interfaces/CallOptions.html|CallOptions} for more details.
    * @returns {Promise} - The promise which resolves to an array.
    *   The first element of the array is Array of [Glossary]{@link google.cloud.translation.v3beta1.Glossary}.
-   *   The client library support auto-pagination by default: it will call the API as many
+   *   The client library will perform auto-pagination by default: it will call the API as many
    *   times as needed and will merge results from all the pages into this array.
-   *
-   *   When autoPaginate: false is specified through options, the array has three elements.
-   *   The first element is Array of [Glossary]{@link google.cloud.translation.v3beta1.Glossary} that corresponds to
-   *   the one page received from the API server.
-   *   If the second element is not null it contains the request object of type [ListGlossariesRequest]{@link google.cloud.translation.v3beta1.ListGlossariesRequest}
-   *   that can be used to obtain the next page of the results.
-   *   If it is null, the next page does not exist.
-   *   The third element contains the raw response received from the API server. Its type is
-   *   [ListGlossariesResponse]{@link google.cloud.translation.v3beta1.ListGlossariesResponse}.
-   *
-   *   The promise has a method named "cancel" which cancels the ongoing API call.
+   *   Note that it can affect your quota.
+   *   We recommend using `listGlossariesAsync()`
+   *   method described below for async iteration which you can stop as needed.
+   *   Please see the
+   *   [documentation](https://github.com/googleapis/gax-nodejs/blob/master/client-libraries.md#auto-pagination)
+   *   for more details and examples.
    */
   listGlossaries(
     request: protos.google.cloud.translation.v3beta1.IListGlossariesRequest,
@@ -1442,18 +1478,7 @@ export class TranslationServiceClient {
   }
 
   /**
-   * Equivalent to {@link listGlossaries}, but returns a NodeJS Stream object.
-   *
-   * This fetches the paged responses for {@link listGlossaries} continuously
-   * and invokes the callback registered for 'data' event for each element in the
-   * responses.
-   *
-   * The returned object has 'end' method when no more elements are required.
-   *
-   * autoPaginate option will be ignored.
-   *
-   * @see {@link https://nodejs.org/api/stream.html}
-   *
+   * Equivalent to `method.name.toCamelCase()`, but returns a NodeJS Stream object.
    * @param {Object} request
    *   The request object that will be sent.
    * @param {string} request.parent
@@ -1474,6 +1499,13 @@ export class TranslationServiceClient {
    *   Call options. See {@link https://googleapis.dev/nodejs/google-gax/latest/interfaces/CallOptions.html|CallOptions} for more details.
    * @returns {Stream}
    *   An object stream which emits an object representing [Glossary]{@link google.cloud.translation.v3beta1.Glossary} on 'data' event.
+   *   The client library will perform auto-pagination by default: it will call the API as many
+   *   times as needed. Note that it can affect your quota.
+   *   We recommend using `listGlossariesAsync()`
+   *   method described below for async iteration which you can stop as needed.
+   *   Please see the
+   *   [documentation](https://github.com/googleapis/gax-nodejs/blob/master/client-libraries.md#auto-pagination)
+   *   for more details and examples.
    */
   listGlossariesStream(
     request?: protos.google.cloud.translation.v3beta1.IListGlossariesRequest,
@@ -1498,10 +1530,9 @@ export class TranslationServiceClient {
   }
 
   /**
-   * Equivalent to {@link listGlossaries}, but returns an iterable object.
-   *
-   * for-await-of syntax is used with the iterable to recursively get response element on-demand.
+   * Equivalent to `listGlossaries`, but returns an iterable object.
    *
+   * `for`-`await`-`of` syntax is used with the iterable to get response elements on-demand.
    * @param {Object} request
    *   The request object that will be sent.
    * @param {string} request.parent
@@ -1521,7 +1552,18 @@ export class TranslationServiceClient {
    * @param {object} [options]
    *   Call options. See {@link https://googleapis.dev/nodejs/google-gax/latest/interfaces/CallOptions.html|CallOptions} for more details.
    * @returns {Object}
-   *   An iterable Object that conforms to @link https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols.
+   *   An iterable Object that allows [async iteration](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols).
+   *   When you iterate the returned iterable, each element will be an object representing
+   *   [Glossary]{@link google.cloud.translation.v3beta1.Glossary}. The API will be called under the hood as needed, once per the page,
+   *   so you can stop the iteration when you don't need more results.
+   *   Please see the
+   *   [documentation](https://github.com/googleapis/gax-nodejs/blob/master/client-libraries.md#auto-pagination)
+   *   for more details and examples.
+   * @example
+   * const iterable = client.listGlossariesAsync(request);
+   * for await (const response of iterable) {
+   *   // process response
+   * }
    */
   listGlossariesAsync(
     request?: protos.google.cloud.translation.v3beta1.IListGlossariesRequest,
@@ -1635,9 +1677,10 @@ export class TranslationServiceClient {
   }
 
   /**
-   * Terminate the GRPC channel and close the client.
+   * Terminate the gRPC channel and close the client.
    *
    * The client will no longer be usable and all future behavior is undefined.
+   * @returns {Promise} A promise that resolves when the client is closed.
    */
   close(): Promise<void> {
     this.initialize();
diff --git a/packages/google-cloud-translate/synth.metadata b/packages/google-cloud-translate/synth.metadata
index 8463aa7f94b..ea22fe3dda3 100644
--- a/packages/google-cloud-translate/synth.metadata
+++ b/packages/google-cloud-translate/synth.metadata
@@ -3,23 +3,15 @@
     {
       "git": {
         "name": ".",
-        "remote": "https://github.com/googleapis/nodejs-translate.git",
-        "sha": "77a873f5854fb1ad5065e332e144ecc2a4b398b7"
-      }
-    },
-    {
-      "git": {
-        "name": "googleapis",
-        "remote": "https://github.com/googleapis/googleapis.git",
-        "sha": "7e1a21195ede14f97f7da30efcff4c6bac599bb5",
-        "internalRef": "330665887"
+        "remote": "git@github.com:googleapis/nodejs-translate.git",
+        "sha": "205c645cdf08fbf94a583b06ff921b54e5b56f7b"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "ba9918cd22874245b55734f57470c719b577e591"
+        "sha": "1f1148d3c7a7a52f0c98077f976bd9b3c948ee2b"
       }
     }
   ],
@@ -96,6 +88,7 @@
     "README.md",
     "api-extractor.json",
     "linkinator.config.json",
+    "package-lock.json.515292936",
     "protos/google/cloud/translate/v3/translation_service.proto",
     "protos/google/cloud/translate/v3beta1/translation_service.proto",
     "protos/protos.d.ts",
@@ -103,6 +96,7 @@
     "protos/protos.json",
     "renovate.json",
     "samples/README.md",
+    "samples/package-lock.json.3537124090",
     "src/v3/index.ts",
     "src/v3/translation_service_client.ts",
     "src/v3/translation_service_client_config.json",
diff --git a/packages/google-cloud-translate/system-test/fixtures/sample/src/index.ts b/packages/google-cloud-translate/system-test/fixtures/sample/src/index.ts
index 8ef08d3c3da..f2c2d83a07e 100644
--- a/packages/google-cloud-translate/system-test/fixtures/sample/src/index.ts
+++ b/packages/google-cloud-translate/system-test/fixtures/sample/src/index.ts
@@ -18,8 +18,15 @@
 
 import {TranslationServiceClient} from '@google-cloud/translate';
 
+// check that the client class type name can be used
+function doStuffWithTranslationServiceClient(client: TranslationServiceClient) {
+  client.close();
+}
+
 function main() {
-  new TranslationServiceClient();
+  // check that the client instance can be created
+  const translationServiceClient = new TranslationServiceClient();
+  doStuffWithTranslationServiceClient(translationServiceClient);
 }
 
 main();
diff --git a/packages/google-cloud-translate/system-test/install.ts b/packages/google-cloud-translate/system-test/install.ts
index 4c1ba3eb79a..39d90f771de 100644
--- a/packages/google-cloud-translate/system-test/install.ts
+++ b/packages/google-cloud-translate/system-test/install.ts
@@ -20,32 +20,32 @@ import {packNTest} from 'pack-n-play';
 import {readFileSync} from 'fs';
 import {describe, it} from 'mocha';
 
-describe('typescript consumer tests', () => {
-  it('should have correct type signature for typescript users', async function () {
+describe('📦 pack-n-play test', () => {
+  it('TypeScript code', async function () {
     this.timeout(300000);
     const options = {
-      packageDir: process.cwd(), // path to your module.
+      packageDir: process.cwd(),
       sample: {
-        description: 'typescript based user can use the type definitions',
+        description: 'TypeScript user can use the type definitions',
         ts: readFileSync(
           './system-test/fixtures/sample/src/index.ts'
         ).toString(),
       },
     };
-    await packNTest(options); // will throw upon error.
+    await packNTest(options);
   });
 
-  it('should have correct type signature for javascript users', async function () {
+  it('JavaScript code', async function () {
     this.timeout(300000);
     const options = {
-      packageDir: process.cwd(), // path to your module.
+      packageDir: process.cwd(),
       sample: {
-        description: 'typescript based user can use the type definitions',
+        description: 'JavaScript user can use the library',
         ts: readFileSync(
           './system-test/fixtures/sample/src/index.js'
         ).toString(),
       },
     };
-    await packNTest(options); // will throw upon error.
+    await packNTest(options);
   });
 });