Translation of names can help somewhat - it can give a rough idea, but can be a bit dodgy in terms of reconstructing sounds, too. Another way to help reconstruct the sounds of language is poety (if it has some sort of rhyme scheme, anyway). That way you can tell what should sound like what to some extent. Also, sometimes another language was written using the language-in-question's character set - for example, Old Irish scribes wrote a bunch of Latin in with the Old Irish - so that can help give you an idea (granted you know how the other language was supposed to sound, which opens another bag of worms). Also, since spelling was often not standardized in many ancient languages, the range of spellings of any given word were phonetic and can help give people an idea of what it should have sounded like, approxamately anyway.
The long and short of it is that you'll never know really how something was acutally pronounced and it was probably pronounced ten different ways in ten different places, too, like many languages today. Think of how someone in California "car" then think of someone in Boston.
Thus endeth the linguistic ramble.