For some reason am finding myself reading things about Mandarin language-learning lately. I have no obvious purpose or need to learn chinese, but it's just kinda neat. Dunno. Languages. The phonology isn't nearly as scary as I once thought. The distinction between Polish sz /ʂ/ and si /ɕ/, which, thanks to K, I am somewhat more familiar with, is afaict the same as the difference between pinyin sh and x (and analogously ch /t͡ʂʰ/ and q /t͡ɕʰ/, and zh /t͡ʂ/ and j /t͡ɕ/). The association between vowels and pinyin spelling's a bit messed up, but none of the vowels themselves seem that hard. ü I know from french. The [ɤ] is a little weird, (as in 和 he2 or 个 ge4) but I think I'm getting it. Tones are slightly scary but nowadays there is shit-tons of youtube content to listen to for examples. Hearing and producing aspiration differences is still tough for me.
Learning 汉字 is helped slightly by having taken a tiny smattering of japanese back in the day. Some of the numbers and simpler characters have stuck with me, at least semantically. I think I can recall either the meaning or reading of in the ballpark of 50-100 of them.