diff --git a/build-ios.sh b/build-ios.sh
index 855b92dd6..e5fa9e2a0 100755
--- a/build-ios.sh
+++ b/build-ios.sh
@@ -127,7 +127,8 @@ cmake --build build/os64 --target install
 echo "Generate xcframework"
 
 mkdir -p "build/simulator/lib"
-for f in libkaldi-native-fbank-core.a libsherpa-onnx-c-api.a libsherpa-onnx-core.a; do
+for f in libkaldi-native-fbank-core.a libsherpa-onnx-c-api.a libsherpa-onnx-core.a \
+         libsherpa-onnx-fst.a libsherpa-onnx-kaldifst-core.a libkaldi-decoder-core.a; do
   lipo -create build/simulator_arm64/lib/${f} \
                build/simulator_x86_64/lib/${f} \
        -output build/simulator/lib/${f}
@@ -138,12 +139,18 @@ done
 libtool -static -o build/simulator/sherpa-onnx.a \
   build/simulator/lib/libkaldi-native-fbank-core.a \
   build/simulator/lib/libsherpa-onnx-c-api.a \
-  build/simulator/lib/libsherpa-onnx-core.a
+  build/simulator/lib/libsherpa-onnx-core.a  \
+  build/simulator/lib/libsherpa-onnx-fst.a   \
+  build/simulator/lib/libsherpa-onnx-kaldifst-core.a \
+  build/simulator/lib/libkaldi-decoder-core.a
 
 libtool -static -o build/os64/sherpa-onnx.a \
   build/os64/lib/libkaldi-native-fbank-core.a \
   build/os64/lib/libsherpa-onnx-c-api.a \
-  build/os64/lib/libsherpa-onnx-core.a
+  build/os64/lib/libsherpa-onnx-core.a \
+  build/os64/lib/libsherpa-onnx-fst.a   \
+  build/os64/lib/libsherpa-onnx-kaldifst-core.a \
+  build/os64/lib/libkaldi-decoder-core.a
 
 
 rm -rf sherpa-onnx.xcframework
diff --git a/build-swift-macos.sh b/build-swift-macos.sh
index a346adbb5..a1b06205c 100755
--- a/build-swift-macos.sh
+++ b/build-swift-macos.sh
@@ -26,4 +26,7 @@ make install
 libtool -static -o ./install/lib/libsherpa-onnx.a \
   ./install/lib/libsherpa-onnx-c-api.a \
   ./install/lib/libsherpa-onnx-core.a \
-  ./install/lib/libkaldi-native-fbank-core.a
+  ./install/lib/libkaldi-native-fbank-core.a \
+  ./install/lib/libsherpa-onnx-fst.a \
+  ./install/lib/libsherpa-onnx-kaldifst-core.a \
+  ./install/lib/libkaldi-decoder-core.a
diff --git a/sherpa-onnx/c-api/c-api.cc b/sherpa-onnx/c-api/c-api.cc
index c08a3fef6..3f6b35466 100644
--- a/sherpa-onnx/c-api/c-api.cc
+++ b/sherpa-onnx/c-api/c-api.cc
@@ -488,6 +488,11 @@ int32_t SherpaOnnxVoiceActivityDetectorEmpty(
   return p->impl->Empty();
 }
 
+int32_t SherpaOnnxVoiceActivityDetectorDetected(
+    SherpaOnnxVoiceActivityDetector *p) {
+  return p->impl->IsSpeechDetected();
+}
+
 SHERPA_ONNX_API void SherpaOnnxVoiceActivityDetectorPop(
     SherpaOnnxVoiceActivityDetector *p) {
   p->impl->Pop();
diff --git a/sherpa-onnx/c-api/c-api.h b/sherpa-onnx/c-api/c-api.h
index a5a341d27..b79b83072 100644
--- a/sherpa-onnx/c-api/c-api.h
+++ b/sherpa-onnx/c-api/c-api.h
@@ -570,6 +570,11 @@ SHERPA_ONNX_API void SherpaOnnxVoiceActivityDetectorAcceptWaveform(
 SHERPA_ONNX_API int32_t
 SherpaOnnxVoiceActivityDetectorEmpty(SherpaOnnxVoiceActivityDetector *p);
 
+// Return 1 if there is voice detected.
+// Return 0 if voice is silent.
+SHERPA_ONNX_API int32_t
+SherpaOnnxVoiceActivityDetectorDetected(SherpaOnnxVoiceActivityDetector *p);
+
 // Return the first speech segment.
 // It throws if SherpaOnnxVoiceActivityDetectorEmpty() returns 1.
 SHERPA_ONNX_API void SherpaOnnxVoiceActivityDetectorPop(
diff --git a/swift-api-examples/SherpaOnnx.swift b/swift-api-examples/SherpaOnnx.swift
index 11dabcda0..53637011c 100644
--- a/swift-api-examples/SherpaOnnx.swift
+++ b/swift-api-examples/SherpaOnnx.swift
@@ -548,7 +548,11 @@ class SherpaOnnxVoiceActivityDetectorWrapper {
   }
 
   func isEmpty() -> Bool {
-    return SherpaOnnxVoiceActivityDetectorEmpty(vad) == 1 ? true : false
+    return SherpaOnnxVoiceActivityDetectorEmpty(vad) == 1
+  }
+
+  func isDetected() -> Bool {
+    return SherpaOnnxVoiceActivityDetectorDetected(vad) == 1
   }
 
   func pop() {