Ask HN: What do you look for when choosing a new programming language?

I've recently finished quite a bit of reading material on compiler construction and design, and a fair bit of PLT. I wanted to survey HN users on the pain points of languages they may use in production, and what they look for when selecting a new language or framework. This may or may not culminate into a new project, but either way this exercise will be useful to me (and perhaps you as well).