Accessibility audio, option for audio levelling avaliable

Under speaker audio in volume and audio output you have HDMI audio, optical audio and the 3rd would be greyed usually

2nd
option is the one where you would choose bitstream out and 3rd is the format. If you dont see this you may also need to check if your xbox is up-to-date as these options should be avaliable

When I go to setting my options are general, account, system, devices and streaming, preferences, ease of access.

And optical audio is not an option in the general>volume and audio output settings

cc from UFC website: AUDIO FIX - after download the title update, your audio levels for Music, Dialogue, and SFX are all set by default to zero. To fix this, simply go to your Options Menu and set each to your desired level. You will only need to do this
once per profile.

Definitely check the in game Audio options as you may have chat features disabled. Also when you have your mic connected, press the middle 'Menu' button on the controller and check the Audio settings on that menu and adjust some of the levels and see if
that helps.

If the game you're playing is supported in another language or multiple languages then, in the settings/options of whatever game it is there should be an option to change the voice and dialouge languages. Its most likely gonna be under audio/sound. If you
don't have that option then the game isn't support for any language outside of English or if the option is there and you can't find the one you want you may only have a small selection of languages that the title is supported in.

Language support is avaliable at the discretion of the developer/publisher. You may wanna check online to see what languages its avaliable in before buying or downloading next time.