Hi there! I understand that the sound input in the Wlingua app on your Android device (OS version 16) has stopped working. Let’s work through this together to get it fixed.

First, could you tell me a bit more? For example:
- Are you trying to use the microphone for speaking exercises or another feature?
- Does the app not register any sound at all, or is it only certain parts of the app?
- Have you recently updated the app or your phone’s OS?

In the meantime, here are some straightforward steps to try:

1. Check App Permissions:
- Go to your phone’s Settings > Apps > Wlingua.
- Tap on Permissions.
- Ensure the microphone permission is granted. If it’s off, toggle it on.

2. Restart the App & Device:
- Close the Wlingua app completely (remove it from recent apps).
- Restart your phone to refresh all system processes.
- Open the app again and test the sound input.

3. Check for Other Apps Using Mic:
- Sometimes, if another app is actively using the microphone, Wlingua cannot access it.
- Close any apps that might be using the microphone, like voice recorders or calls.

4. Update the App:
- Open Google Play Store.
- Search for Wlingua and check if there’s an update available. If so, update it.

5. Clear Cache (without losing your progress):
- Go to Settings > Apps > Wlingua > Storage.
- Tap “Clear Cache” (not “Clear Data” which might erase progress).

If you’ve already tried any of these or if this issue persists, let me know, and we can dive into more advanced troubleshooting.

Also, if the app has a settings section for voice or microphone sensitivity, we can check those as well.

Looking forward to helping you get this working! Are you able to try the above steps and tell me what happens?