I go the other way -- I write in Python by default, then only go to another language if I specifically need it, for example these scenarios: (a) Python isn't f

I go the other way -- I write in Python by default, then only go to another language if I specifically need it, for example these scenarios: (a) Python isn't fast enough, and Pypy doesn't make it fast enough, or isn't a viable option in the target environment. So you write in C, OpenCL or assembly language. (b) A vital library or other dependency can't talk to Python and you can't quickly find or write a reimplementation or bridge. (c) Python isn't supported in the target environment, for example, the web browser [1] or the iPhone. [1] Yes, yes, I know, things like Skulpt and Pyjamas exist. But I think those dependencies are too heavy for a lot of projects.