Not forgetting of course that Twitter almost certainly uses several languages on the backend, and has it entwined in their infrastructure. As TFA says:

"One former Tesla engineer, who spoke on the condition of anonymity to candidly describe the matter but was not involved, said Tesla engineers would have trouble capably assessing Twitter’s code. Distributed systems, the large-scale and spread-out network that Twitter is composed of, are not the automaker’s specialty, the person said."