The _fundamentals_ of most new languages one might typically use take a pretty short time (weeks, not months) to learn, for experienced developers. Most signifi

The _fundamentals_ of most new languages one might typically use take a pretty short time (weeks, not months) to learn, for experienced developers. Most significant real projects will need at least a couple of prototypes/POC's at the beginning. Thus a brand new project is a great time to learn a new language, you can make your beginner mistakes in code which will never ship. This goes back to that "innovation tokens" thing though, a new language is one innovation and you don't want too many others at the same time.