When it comes to hiring programmers among the _last_ things you want to consider is familiarity with a particular language and platform. Look for programming, interpersonal, and communications skills first. Those skills are hard to come by. Languages and platforms can be learned quickly enough.

A .NET programmer, for example, can become a productive Java, Ruby, Python, Swift, Dart, Go programmer in just a few weeks. On the other hand, a very adept Swift programmer who can't look you in the eye, or communicate with team mates, will chronically fall short.