As to why languages have difficult spots, linguists are hard pressed to say, and usually explain them with reference to the given culture and environment of the language. Nevertheless, conclusive answers regarding grammar and pronunciation are still few and the field remains virgin territory.
語言學家可以找到的唯一解釋是因為「需要」，像生長在冰天雪地的愛斯基摩人，對「雪」的詞彙與形容詞特多；中文裡頭親屬用語很多等。但語言學家迄今仍找不出為什麼某些語言文法特難、某些語言發音特異；對語言學家來說，這是一個大可開發的「處女地」。