Also, those numbers actually suggest that by far the most active language group (relatively speaking) on twitter are the Dutch speakers, who are almost all Europeans. Actually, I thought the number and growth for Dutch had to be a mistake, but other sources [1] do suggest the same trends. I'm still sceptical about the numbers though, especially German being hardly used seems at odds with older data about twitter usage [2].

[1]http://www.comscore.com/Press_Events/Press_Releases/2011/4/T... [2]http://blog.sysomos.com/2010/01/14/exploring-the-use-of-twit...