The aistear programme (pronounced ash ter) is in use in infant classes in Belgrove JBS and is a play-based programme which drays heavily on the work of the Russian psycholinguist Lev Vygotsky. His thesis was that play was crucial to the development of language in children. This article makes the case for play-based early years provision as well as for starting formal school as close to 5 years as possible. While written in the context of British schools, it may well contain important messages for us.
You can read the article here: http://theconversation.com/hard-evidence-at-what-age-are-children-ready-for-school-29005