Back when I used to wait tables, the other waitresses and I would joke to each other about our “waitress voice”, which were the personas we all subconsciously seemed to slip into when talking to customers. They varied somewhat, but they were all uniformly saccharine, with slightly higher-pitched voices, and with the general demeanor as though you were talking to someone you didn’t think was very bright. Every LLM’s writing “voice” reminds me of that.