Google Search, especially when coding. Nothing else so far.
Chat GPT works great at converting Wolfram Alpha to latex. Wolfram refuses to convert it unless you pay, in order to keep its ecosystem closed.
Past A1-level, I'm never studying a language again using anything but LLMs.
I mean maybe spaced repetition for flashcards, that's it.
It's a joy putting stuff into an LLM, getting it to break down difficult constructions for me, talking to it and asking it what it means... endless patience.
Worth every penny.
+1. This is the one use I rave about. I look forward to voice input/output getting better in order to have practice conversations with it — ones that correct my pronunciation along the way and provide other guided exercises at the right times, perhaps with a built-in spaced repetition system.