And the way they transform data isn't by transforming words. The layers transform high dimensional vectors - a format very alien to us. It's not obvious that these vectors must encode concepts from the vocabulary.
Edit: the paper claims that it's only J-space concepts that need to map to English words, other forms of cognition that are more 'practiced' and don't require so much reasoning bypass the J-space and can work in non-verbal subspaces. So that's the answer.
all kind of math structures were found in mammals brains - fourier transforms (well, not exactly), ballistic equations, Gabor filters
who knows how exactly we approximate the magnitude of a math operations, maybe we also use helices
my point is that we dont know if what we discover the neural networks doing (helical manifolds) is actually the same thing a brain converges on, or not
and there is an implicit bias here - evolution created language, and we forced neural networks to also evolve to be good at it. so it wouldn't be surprising to find some convergence, this particular kind of language turned out to work well (words, linear sentences, grammar)