Which languages?

http://www.quora.com/Why-do-most-professional-non-HFT-algorithmic-trading-firms-use-C++-C-Java-for-strategy-backtesting-and-creation-when-other-languages-like-R-or-Python-provide-some-very-good-frameworks-to-quickly-iterate-through-multiple-early-prototypes-of-differing-strategies