Some work on linguistic evolution reveals that processes similar to biological adaptation may be at play, overturning an emphasis on randomness and historical drift:
The researchers found striking relationships between the demographic properties of a language — such as its population and global spread — and the grammatical complexity of those languages. Languages having the most speakers — and those that have spread around the world — were found to have far simpler grammars, specifically morphology, than languages spoken by few people and in circumscribed regions. For example, languages spoken by more than 100,000 people are almost six times more likely to have simple verb conjugations compared to languages spoken by fewer than 100,000 people....
Applied to English....
"English, for all its confusing spelling and exceptions — if a baker bakes, what does a grocer do? — has a relatively simple grammar," Lupyan said. "Verbs are easy to conjugate and nouns are mostly pluralized by adding 's.' In comparison, a West African language like Hausa has dozens of ways to make nouns plural and in many languages — Turkish, Aymara, Ladakhi, Ainu — verbs like 'to know' have to include information about the origin of the speaker's knowledge. This information is often conveyed using complex rules, which the most widely-spoken languages on earth like English and Mandarin lack."
Languages, spoken over wider populations, tend to become morphologically simpler, is the base of their thesis. It is a statistical study, with many exceptions, that reveals certain social factors have an influence on linguistic development. It also pins down the myth that English is one of the more difficult languages to learn.