I've been following this stuff for years, it's fascinating. I'm particularly interested in the recent practical applications like Minimal English and it's equivalent in other languages. For those that don't know, unlike other minimalist English subsets which usually focus on learnability or clarity, Minimal English focuses on maximum translatability.
I'm going to get silly now, but I can't help but think the semantic primes - if you can avoid thinking of them as words or even conscious experience - represent some core set of cognitive axioms, like the primitive elements for constructing mental models. As you go to simpler life forms the "word list" would get smaller. If there is any truth to that, I wonder what potential primitives we are missing that would allow us to think more complex thoughts and whether you could measure species intelligence by their "vocabulary" and working out what concepts can't be expressed when one of the primitives is missing. What would happen if you lost the concept of above'ness?
The other thing I find interesting and it might be no more than a coincidence, is how there is only the numbers one and two and then you have to use many or more. This in some way matches up with the ideas of the Parallel individuation system[1] whereby young children can only precisely recognize quantities up to 3, or 1 + 2 and an adult can only precisely recognize quantities up to 4, or 2 + 2. After that, the brain uses the Approximate number system[2]. So it's like there are only 2 slots to place a quantity.
[1] https://en.wikipedia.org/wiki/Parallel_individuation_system
[2] https://en.wikipedia.org/wiki/Approximate_number_system