The Piraha language is probably inadequate for developing interstellar travel. As was English hundreds of years ago. You need numbers, and names for concepts like energy, mass, momentum, and time.
Given that there is so much of physics that we have yet to understand (assuming what we think to be true is actually true), and given the infinite possibilities of what forms alien life could take, you can't make any assumptions about what sort of language they'd have. This was a point they briefly tried to make in the movie.
But I'd bet on the OPs hypothesis as well. At a guess, most space travelling species will have had to climb a similar developmental curve to our own - including agriculture (or whatever passes for it in their biosphere, unless they photosynthesize themselves), tool making, metal smelting, nuclear power, etc. etc.