You all have spoken well. I have travelled to majority of the eastern part of Nigeria and the dorminant language there is igbo. Infact, there is no other language there outside igbo as you have to protest before anyone will talk to you in english. same thing is applicable in the western and northern parts of the country. Even in the smaller ethnic group states of akwa ibom the same happens. In actual fact, no other language dorminates the other-everyone rules his territory which explains why yoruba is spoken is Lagos. My friends who did teaching practice in Lagos confirm that there are kids in Lagos who can't speak english even though they live in a cosmopolitan environment.This is replicated across the country. As for abroad i don't have any facts on that. Musicwise one would find out that the yorubas like to sing in their language and the music is popular only in the west where they dorminate so the younger yoruba artist now mix english and yoruba which makes their music accepted by others. Same thing happens in the movie industry where yoruba movie is seen only in the west ( the west is less than one-quarter of Nigeria)