Bizarre things my mind conjures up

[Thumpalumpacus]

Mankind began writing before he could speak.

There's a couple of lines of reasoning against this.

1) How did they agree on what the written symbols meant without using speech to make that agreement?

2) Dogs and other animals may be trained to understand, if not speak, language. This implies that the ability to understand spoken language is more primal than written language.

Written language has a documented history of perhaps 6,000 years or so. Do you think that H. Sapiens Sapiens, extant for at least 150,000 years before that time, didn't develop spoken language, given evidence from both the animal kingdom (because animals use understood vocalizations) and the evolution of both the hyoid bone and Broca's area?

Also, many native tribes from all over the world have or had no written alphabet, but most certainly have or had distinct spoken languages.