Reili Argus, a professor of Estonian at the TU Institute of Estonian Language and Culture says mastering a language does not depend on how difficult or complicated a language is deemed to be. Children are able to master the most complicated grammar at an early age and with little to no effort. Turns out the richer the grammar is, the earlier the children grasp it. - See more at: http://www.tlu.ee/en/News/2906/one-minute-lecture-reili-argus-is-estonian-difficult-to-learn