I found this on wiki...
1. Mandarin Chinese (1.12 billion)
2. English (480 million)
3. Spanish (320 million)
4. Russian (285 million)
5. French (270 million)
6. Hindi/Urdu (250 million)
7. Portuguese (248 million)
8. Arabic (221 million)
9. Bengali (185 million)
10. Japanese (133 million)
11. Punjabi (130 million)
12. German (100 million)
http://en.wikipedia.org/wiki/List_of_languages_by_total_number_of_speakers
The number for english seems a little low to me.
add all the native speakers in the world from:
USA
canada
UK
autralia
new zealand
south africa
israel
various tiny and island nations
plus all the other people in the world who speak english as a second language and you only get 480M?? I don’t know about that.
Perhaps they are counting only those who are fluent in the language?
So far, with the exception of a smattering of Arabic, I've never learnt any non-Indo-European language. I find I can see some threads of similarity between various Indo-European languages which make it easier to pick up. What about you?