i dont have voice on any sl viewer

[Mitzymoo Clawtooth]

no matter what sl viewer i use i am unable to use voice and am unable to hear other people talking

[valerie Inshan]

See the recommendations in this KB:

 

http://community.secondlife.com/t5/English-Knowledge-Base/Using-voice-chat/ta-p/700169

In the official viewer (I'm not sure if this work the same in other viewers), you may also check that voice is enabled in the debug settings. Go the advanced menu > debug settings > EnableVoiceChat, togle between true and false, and see if this helps.