An experiment with phonetic writing

[rikforto]

I was talking about how, in any case, he would perceive the words aurally differently, and what he would write would be incomprehensible to a native speaker.

Right, and I don't understand how he is having conversations in the language and perceiving the language different from how it is spoken. Perhaps a transparent example---remembering that I do not speak French and cannot read a made-up representation of it in any event---might help