Also note that this will overwrite voice, as that's the intended feature. In A3, a 'voice', or 'speaker' cannot have two languages. If the VA recorded in both, then that would be a different story. Otherwise, there's 14 American voices and 3 Persian voices [Or lost count.]. If you want to make a soldier that speaks American 12's voice to speak Persian, you have to change his voice to Persian 1, 2 or 3. By the way, do note that this will only affect automatic speaking such as group commands. Custom message/radio will not be affected.
How to use example:
this setSpeaker "Male01PER";
Added 5 minutes later:
Sorry, i thought it was A3. The above method only works in A3. Otherwise, look in there and set up the description.ext as needed. Example identity entry is given there.
Then, use setIdentity to uh, set the identity... It's the only way in Arma 2.
Added 16 minutes later:
Oh hey and just some extra stuff.
A2 doesn't have the entry "nameSound" in cfgIdentities, hence do not use that, because if you do, A2 might not recognize the description.ext pretty well.