uh huh...and how well do these children read and write??
There is a reasonable body of evidence that musical instruction in the young leads to higher levels of literacy.http://ecrp.uiuc.edu/v10n1/bolduc.html
is a good place to start. I'll drop in this: http://www.abcmusicandme.com/images/abc%20white%20paper.pdf
as well - but it is a study commisioned by someone selling something, so pinch of salt there.
Note - it is still to be determined if it is correlation (More musically inclined children are already more likely to enjoy learning) or causation (Learning music promotes literacy). Still interesting to look at.
Looking back into history, most people learned through songs and poems, even if they couldn't read or write.
Anne McCaffery (wonderful writer if you like sci-fi/fantasy) made sure that one of the biggest guilds on Pern was the bards hall, calling on her knowledge of Slavonic history and Irish traditions.