Did one gorilla get angry with another gorilla and decide to start a new language?
This debate falls at the first hurdle in my opinion, as the op is suggesting that humans evolved from gorillas. Evolution indicates that although humans and gorillas are related, we evolved over millions of years from seperate lines therefore the fact that humans have developed the power of speech and gorillas have not is quite inconsequential.
Divergence of the human lineage from other Great Apes
Species close to the last common ancestor of gorillas, chimpanzees and humans may be represented by Nakalipithecus fossils found in Kenya and Ouranopithecus found in Greece. Molecular evidence suggests that between 8 and 4 million years ago, first the gorillas, and then the chimpanzees (genus Pan) split off from the line leading to the humans; human DNA is approximately 98.4% identical to that of chimpanzees when comparing single nucleotide polymorphisms (see human evolutionary genetics).