surely Neuralese interpreters can be made that turn the chain of numbers into an English description?

This is the premise of Natural Language Autoencoders.

https://www.anthropic.com/research/natural-language-autoenco...

I think this is correct. But the article is also correct (If a bit breathless and overstating on the risk): having to reinterpret neuralese is a layer of indirection which introduces effort and inaccuracy