I’m somewhat familiar with how the avoidance register works in Walpiri, and the switch is solely based on the social relationship, not the names involved.

It’s a fairly complex sub-language - there’s a different set of words that get used only for the avoidance register or are very generic terms from standard speech, and the grammar is simplified. The pronunciation is also shifted a bit, iirc (I want to say it uses creaky voice, but I’m not sure).