Are there some statistics about languages?
I was wondering if there are statistics available about which languages are being learned the most? or learners of which language are active the most? and alike.
I am not sure what country your talking about but you can try World Factbook – CIA, searching the census, the statistics department or bureau in country of interest. It really depends on the country, but many do keep data regarding language diversity and usage. You may also find information at one of these agencies on language activity.
I think he means what languages are being learned by the users of duolingo, and which users are most active on duolingo... - If this is the case, I don't know. This has been asked before, and hasn't received any official responses (That I know of).