Hi Mehdi,
About the first question, unfortunately right now it's not possible. The good news is that it's in our roadmap and this feature will be released in the future, along this year.
Related with the language, you could change the session language adding locale to the request. If you have different locale resources in your Sentilo instance, you could change from the default ones to others like this:
This will only affect your current session, of course.
Regards,
Sentilo Team.