I'm Japanese, and I can still usually spot AI-generated Japanese by its word choice. Some words, like 実務 (practical work) and 帳簿 (a ledger), turn up far more often than they should. Casual ones like 効く (to work well, to be effective) and 刺さる (to pierce > to resonate, to hit home) get used where...
Source: [Hacker News](https://news.ycombinator.com/item?id=49338865)