If you are talking about an ancient language with no writing
system, it would be virtually impossible to decipher the sounds of
it without context.
However, one place to start would be finding a linguist to help you convert the sounds to IPA (the international phonetic alphabet). This would give you a chance to at least analyze the patterns of words, and see if it's a real language and/or determine it's language family.
If it turned out to be a language isolate, you will never be able to decipher it without context.