When did humans develop language?

The development of language depends on what your beliefs are. I think that language was developed through evolution. Many scientists disagree on how language developed, some have thought that human’s started to speak as soon as our brains became developed enough.Others think language evolved from  the pre historic era, and our ape-like ancestors, which would have made sounds to communicate by changing the pitch, and attempting different sounds, as well as body language, kind of like what a new born baby does now days, they find their own way of communicating with their parents by crying making sounds, and some parents even teach their children a sign for different words.
I think the order in which language evolved was sign, speech and then written. I think this because at first people would have just made noises in form of words and they would have signalled the action at the same time, and then once we learnt to control our voices we would have learnt to speak, cave paintings would have been a popular way to tell stories when there wasn’t a language to speak, and writing would have come last with the formation of letters. Some advantages from writing being invented would be that we can communicate on paper instead of just speaking, in the pre historic era cave paintings were developed to tell stories, and now that writing has been developed that is how we tell stories. Because of writing you can get a richer learning experience, in school not many people would have learnt as much as we have, if we didn’t have writing.