Ask HN: Is it worth learning a new programming language just to build a product?

The last company I worked at was pretty flexible with using whatever programming language made sense for the job, as long as everyone working on that project was comfortable with it. As far as I'm aware, they've kept this attitude to this day.

The biggest downside would appear to be the risk that new developers won't be able to contribute to a project, but I've found this isn't really an issue; most developers that I've met are pretty excited by the chance to use a new language. That excitement may also offset the inertia from using a new language.

Working on a project that benefits from a language's strength is probably the best way to learn that language. If you don't have time pressure, why not?

I am in the exact same situation right now with Erlang/Elixir as the choice. All I want for now is to get the basic functionality working and improve upon it after that. But it takes some time to do that when you have not used the language before. I plan to continue using Erlang/Elixir as my primary language for some time to come, starting with this project. It all boiled down to deciding the deadline for the product to go live. If I have time, I can choose Erlang/Elixir, else I might have to go with something else initially and make the switch later. I haven't made my decision yet, I hope there are some insightful comments here which could help me decide too.