Most developers I know don't have to make "half-assed guesses" about the language they work with, they know it.
Most developers I know learn languages as they go, because there isn't the time nor money for a formal background in any particular language. A good CS degree or software/systems engineering background tends to make the choice of language irrelevant outside of what's the appropriate tool for the job.

Of course there is the occasionally shooting yourself in the foot when inexperienced with a language or a particular implementation of a language. But that's why QA cycles are integral to solid engineering practice. Even "experts" have brain malfunctions from time to time.