There is a fringe theory, that agglutinative languages with consistent vocabulary are more effortless for children to learn. So children would spend less time learning and memorizing words, and could proceed faster to learn other things.
English vocabulary is a patchwork with origins from several different languages, so words with related meaning can look different. Whereas for example Finnish is consistent:
kirjoittaa – to write
kirjailija – writer
kirja – book
kirje – letter
kirjasto – library
kirjallisuus – literature
kirjasin – font
In this way, you can learn the same vocabulary by learning maybe 5x smaller amount of root words.
http://finnish-and-pisa.blogspot.com/