What programming languages do you use?

For our own products, we generally use C++. For client projects we use what they request with Java being the most common although we have done significant projects in C#, Delphi and Ruby.

In some ways, it's unfortunate that the term 'language' came to be used for programming languages. Because unlike human languages, where the acqusition of a new one is a major accomplishment, the majority of programming languages are quite similar and an experienced programmer can usually pick up a new one in a matter of days.