I don't think acquisition will be as much of an issue as recruiting employees will. If you think you can find people to work for your company who either know t

I don't think acquisition will be as much of an issue as recruiting employees will. If you think you can find people to work for your company who either know those languages or can learn them quickly enough to not kill your productivity or your product, then go for it. Otherwise, you may want to think about making some tradeoffs (i.e. node.js over Erlang because you're going to be far more likely to find competent js devs than Erlang devs.) Most acquisitions end up with the founding team contracted to transition for a year or three; during that time the acquiring company either rewrites the IP or ends up with enough qualified people to take it over.