I don't know why you would think that the model can't create new language. That is a trivial activity. For example, I asked GPT5 to read the news and make a new word.

Wattlash /ˈwɒt-læʃ/

n. The fast, localized backlash that erupts when AI-era data centers spike electricity demand—triggering grid constraints, siting moratoriums, bill-shock fears, and, paradoxically, a rush into fixes like demand-response deals, waste-heat reuse, and nuclear/fusion PPAs.