Clients hiring the services of translators often have no idea what they’re really getting for their money. This is especially true when purchasing a translation in which the target language is not understood by the client. Not only can one phrase in any given language be translated in several distinct ways, but it can also be translated badly in an even more ways. Just look at most cartoon/comic fan translations.

You are right. Also, the translators for this software are volunteers, and for most, if not all, languages, the first volunteer got the 'job'. This means the translation quality might vary hugely from language to language (actually, it probably does), but because this is open source software, users can make their own modifications to the translations or report problems with the translations to have those resolved in the next version, etcetera.

However, pokerth users haven't been reporting problems with the translations. This doesn't mean there are no problems, but most users probably don't care enough and/or switch to English if they speak that.

As it stands, a lot of the translations are incomplete (try some if you'd like) which is a bigger problem than a lack of quality in my opinion. This is also due to the process: a week before release the translators get an e-mail with the latest files to be translated, leaving little time to find somebody else if the translator doesn't send the updated files back in time. Which probably happened a lot before the latest release.
Also, there's no linguistic testing before release (I do some testing for Dutch, but it requires compiling svn versions which isn't too easy).
I am a bug maintainer but the translators don't have accounts for the Bug reporting system and I don't have their e-mail, so at this time I wouldn't know how to send them suggestions/bugs even if I got them. If they deliver through the forum, I try to check it a bit though, see for example here: pokerth.net/forum/26-07/3445-portuguese-...translation-071.html

Very long story (sorry) short: your nick is teixeira which means you probably speak Portuguese. Do you have any problems to report for Portuguese (Brazilian Portuguese or Portuguese Portuguese)? You could post in the Bug or the Translation forum, or e-mail me via janheyn at gmail dot com. I'll try.