I'm a native English speaker who learned Bahasa Indonesia in 1984 from adults whose native language was Javanese or Sundanese. Bahasa Indonesia was based on Cou

I'm a native English speaker who learned Bahasa Indonesia in 1984 from adults whose native language was Javanese or Sundanese. Bahasa Indonesia was based on Court Malay or Trading Malay as the language of Indonesia after independence from the Netherlands after 1945. Bahasa Indonesia spoken by people over 21 in 1984 had no distinction between nouns and verbs, and was (for a beginner) admirably short of pesky grammatical rules. But my 18 year old Indonesian contemporaries who had spoken Bahasa Indonesia together at school since age 5 used a much more complex vocabulary and grammar. So I can vouch from experience that grammar and vocabulary of new languages change rapidly with time. As a previous poster said, sign languages for the deaf often evolve as new languages (pidgins/creoles). I think it's fascinating seeing how those new languages diverge and converge to 'expected' language behaviour.