Detail this asset from Unity Store: Original Link
This is a paid asset, but now you can download Android Speech Recognizer Plugin Free.
Android Speech Recognizer Plugin
A Unity plug-in that enhances control over Android speech recognition.
Without any popup or dialog, make the players communicate with your game.
Working on all available Unity versions including Unity 5, it also does not require Unity PRO version.
Adding vocal commands to your game or making your game interact with the user’s speech has never been so simple.
All languages are supported! You can either use the preferred language of your users or set yours.
You can check how easy it is to use this plugin by checking the documentation and all available functions here:
http://www.takohi.com/data/unity/assets/android_speech_recognizer/documentation/
You can also download and run a demo on your Android device by downloading this APK:
http://www.takohi.com/data/unity/assets/android_speech_recognizer/unity-android-speech-recognizer-plugin-demo.apk
The source code of this demo is included in the package.
If you have any questions regarding this product, send us an email at [email protected]