profound comment in a book about grammar

「人間｛にんげん｝の言語｛げんご｝習得｛しゅうとく｝に関して｛かんして｝は

まだまだ不明｛ふめい｝のことが多い｛おおい｝。」

"Concerning human language acquisition, there are still many unknown things."

(Not a very graceful translation into English, but one that is very close to the Japanese original)

from page 252 of

A Dictionary of Intermediate Japanese Grammar {日本語文法辞典ー中級編｝

by Seiichi Makino and Michio Tsutsui, published by The Japan Times、Tokyo, 2007


I agree with Makino and Tsutsui Sensei; we are still learning about the ways humans learn language.