Apex in game chat not working

First thing to do is check that the microphone is working. Depending on platform, how you do that will be different.

Pc/Mac: Go to audio settings and manage input devices, then speak as normal to see if audio is being registered. Ensure that Apex Legends is authorized to use audio input in control panel/system manager

Xbox/PlayStation: Create a party and start talking into it, verify that the audio is being received. There should be a speaker indication that allows you to do so.

If the microphone itself is working, the next thing to check would be your in-game settings.

You want to make sure voice-to text is off, voice chat is enabled, and that the volume slider for voice channel is >0.

If these settings are in place, your audio should be transmitted properly in-game. If it isn’t, that leaves one other main source.

if none of the above fixed the problem, you probably need to reinstall/downgrade your drivers to obtain a working version.