Within five to six months, children can produce the sounds necessary for any human language, and after four to five years, toddlers have mastered pronunciation, grammar, and considerable vocabulary, to the point where they are as quick as pocket calculators.
根據科學家的說法，五、六個月大的嬰兒，就已發展完成「人類所有語言具備的聲音」；只要暴露在一個自然的語言環境，毋需經由教導，幼兒可在四、五年內，很熟練地運用發音、辭彙及語法，反應之快，有如電子計算機。