2 general purpose languages: R and Python. Multi language solutions make sense with languages that specialise. So I'd never write in "Go and Java" for example,

2 general purpose languages: R and Python. Multi language solutions make sense with languages that specialise. So I'd never write in "Go and Java" for example, or "Clojure and C#" or some other pair of general purpose languages. For me, Python usually ends up being the glue. But otherwise, I use a tonne of special purpose stuff. E.g: AMPL Prolog R Lua SQL sed/awk/grep/jq/etc C++ Makefile DSL cron DSL Docker DSL etc.