Here's a quote from a research paper by Professor Susan Hallam, Institute of Education, University of London.
[There is] a strong case for the benefits of active engagement with music throughout the lifespan. In early childhood there seem to be benefits for the development ofperceptual skills which effect learning language subsequently impacting on literacy which isalso enhanced by opportunities to develop rhythmic co-ordination. Fine motor co-ordinationis improved through learning to play an instrument. Music also seems to improve spatialreasoning, one aspect of general intelligence which is related to some of the skills required inmathematics.
You can read the whole paper, The power of music: its impact on the intellectual, social and personal development of children and young people or look for references and articles about it on the web, there are plenty. Or just read on and take away the point I want to make: Musical playtime is a vital part of your young child's daily routine. Like spinach, even more so, musical activities shared between you and your child are wonderful ways to bond with your child and to help your child's developing mind and developing body. Plus, music-making is a lot less messy than, say, creamed spinach and a LOT less green.