There are plenty of oral languages, where the writing only came after contact with missionaries. Māori, and the other Pacific languages, aboriginal etc. And as all other species have some form of oral language, but not written. I’d pretty safe saying that sounds and words long predated the written forms. Unless you know of written only languages that the pronunciation came later?

Writing from language.

A lot of other animals besides humans use vocalisations, and those vocalisations can have quite specific meanings. This makes them a form of communication and demonstrates that encoding meaning in sound is a phenomenon that develops quite readily in nature.

We can also see then that the history of language in humans is those vocalisations becoming increasingly complex and able to represent more numerous concepts and thoughts until they eventually become something we recognise as a full language.

Written language is a mechanism to encode spoken language, but it’s spoken language which came first.

guess where the word “prehistoric” comes from ;)

also, non-human animals have language without writing.