"Some languages require significantly more effort to think in": No. A native speaker of one of those languages can think as effortlessly in them as you can in

"Some languages require significantly more effort to think in": No. A native speaker of one of those languages can think as effortlessly in them as you can in English. "Interpersonal relationships in one language are non-translatable to other languages": I very much doubt that; the Bible (or at least the New Testament) has been translated into thousands of languages. Some concepts require more words in some languages than in others, but in the end it's possible. The real issue for things like Bible translation are plants and especially animals that don't exist in the other cultures, not interpersonal concepts.