This is also how you can identify decent places to work at: look for job postings that emphasize you aren't expected to already know the language.

For example, in the recent "who's hiring" thread, I saw at least two places where they did that: Duckduckgo (they mention only algorithms and data structures and say "in case you're curious, we use Perl") and Stream (they offer a 10-week intro course to Go if you're not already familiar with it). If I remember correctly, Jane Street also doesn't require prior OCaml experience.

The place where I work (bevuta IT GmbH) also allowed me to learn Clojure on the job (but it certainly helped that I was already an expert in another Lisp dialect).

These hiring practices are a far cry from those old style job postings like "must have 10+ years of experience with Ruby on Rails" when the framework was only 5 years old.