Well, just to let you know, I am the author of SleepAnalyser and some other applications. As you can see, SleepAnalyser supports other languages, but has currently just a few languages included.
And as you might guess, I do not speak 20 languages, so most of the languages would have to be distributed by other people. Up to now only 3 people volunteered to supply a translation in their language, even it is very easy and might take you 15..30 minutes.
This means, until more people are willing to invest their time and knowledge, it will stay with those few translations!

P.S. of course I could use Google translation for this, but I am very sure you wouldn't want to use a translation like that