Hi all!
Mappero 3.0+beta7, currently in extras-testing, supports turn-by-turn navigation with vocal announcements in the device user's language.
If there are no sound files for the language in use, then Mappero falls back to interlingua, an international language that you all should learn ;-) This is the "strange language" that I saw being mentioned in some threads here.

So, to help Mappero support your own language, follow these steps:

1. Open the terminal, type "echo $LC_MESSAGES" and keep record of the output (it is a language/country code, for example for Italian it's it_IT)
2. Record yourself while reading the following short sentences (you can install the sound recorder on the N900 too) translated into your language, with one second of silence between them:
   • turn right
   • turn left
   • turn slightly to the right
   • turn slightly to the left
   • take the first exit
   • take the second exit
   • take the third exit
   • continue straight
3. write a post in this thread, specifying your language code and attaching the sound file.
4. hope that people like it :-)

Who will decide which voice is worth being included in the next release of Mappero?

The users! I will periodically check this thread, and I will pick those posts which have been thanked the most.

Unfortunately it's not possible to have more than a single voice for a given language, so only one voice pack for will have to be chosen for each language.