Question

What are two theories that explain the development of humans language

Answer 1

There are many, but the major ones are that

1) language is  somehow saved in our genes, which means that people with better communication skills had a survival advantage over those that didn't and that language is innate. This usually means that the specific parts of language: syntax for example are innate too

2) language was "invented" like writing: and then it was transmitted and changed.