Hello, Please check whether a small white speaker is in the right-bottom corner of the screen. If the X button is allocated either as another function or if there is no microphone connected to the computer, the speakers in the bottom right corner will not appear. Also, it could be also possible that you have disabled the voice chat in your TruckersMP settings. Connect to the server and make sure that the CB radio is turn on, if you want to change a channel press the Y(chat) key and change the channel to "/cb [channel] (for example: /cb 7)" and press hold the x key and speaking.
Press "TAB" key in the game and try to make Sound settings from settings. Make sure that the correct device is selected here. If your device does not appear, try the following steps.
1. Right click the volume icon on your taskbar: http://prntscr.com/lr5rjc
2. Click sounds and then go to the playback tab http://prntscr.com/lr5qoj
3. Right click speakers / the green ticked device and select properties: http://prntscr.com/lr5qfq
4. Go to the advanced tab. Then ensure the following settings in the image are set. Afterwards, press restore defaults. http://prntscr.com/lr5q12
5. Restart TruckersMP.
6. If this fails to work: a reinstall of your audio drivers would also eliminate another possible solution.
Kind Regards,
mexiumut