How Teams Choose Language

In my experience, it's not just one language. A lot of products are built in a variety of languages, based on what the need is.

Python for testing, Haskell for static testing, C++ for high-performance low-level stuff, Lex & Yacc for, well, lexing, etc.

Often there is legacy code around which forces the decision, at least partially.

I partially agree with this because there are companies which chose the language after a critical evaluation. Jet Chose F#