I think this is the right approach to the problem. It's a question of meaning and bootstrapping a minimal language that's based heavily on metaphor (specifically, the conduit metaphor). The answer from this perspective, based on semantic metalanguage, is 800 words. Minimal english, but also minimal across all languages. It's a core language system that's translatable, because language is based on concepts, and those are consistent across natural languages (Chomsky - Universal Grammar).