Marie, I came to Yiddish through German, because if you've got a certain sort of inquisitive linguist's mind, once you know German the obvious ways to go are Yiddish or Dutch, so I knew about the weird Hebrew script already.
I think it's a bit like people who get into Romance languages, if you know Spanish then Italian or Portuguese aren't too difficult... and then eventually you try your hand at Romanian and discover the Slavic influence means most of the grammar you're used to works very differently. When I was in Romania years ago it sounded like Italian mixed with Russian, which I suppose is what it is, so I had to lean into what school Latin I remembered.
Or how I've tried on and off over the years to have a go at Manx, which sounds to me pretty much like Ulster Irish with a Lancashire accent, so the spoken language isn't too much of a stretch, but the anglicised spelling keeps tripping me up. I suppose I can't get past a Gaelic language not having Gaelic spelling conventions, as odd as those spelling conventions might seem to the Sasanaigh 😉
One language I've never heard, but I'm fascinated to know of its existence, is Dungan. It's mostly spoken in the stans of Central Asia by Chinese Muslims (Hui) whose ancestors escaped into the Russian Empire after a failed Muslim uprising against the Chinese state in the 19th century. Their descendants speak a dialect of Mandarin written in Cyrillic script, which sounds irresistibly weird to me.