esp8266-wifi-mic.ino - Arduino IDE file for esp8266, nodemcu or wemos d1 mini.
conv.sh - convert from raw audio to 16-bit WAV and receive text from Yandex SpeechKit Cloud.
test16.wav - sample.
speech.py - python3 script speech2text.
The microphone(max4466) is connected to A0 in esp8266 esp8266 transmit raw audio to MQTT server. conv.sh converting audio and with yandex speechkit getting text.
Video: Youtube
tip: use node-red to save the RAW file