in lesson 5 in my book 4 (which corresponds to lesson on the website) there's this sentence: DOUYATTE NIHONGO *WO* JOUZU NI NARIMASUKA. (How do I become skilled in Japanese?) I would expect it to be DOUYATTE NIHONGO *GA* JOUZU NI NARIMASUKA. NARU I know is an intransitive verb, so it can't have a direct object. But WO/ O is the direct object marker. So what am I missing? Or is it a mistake in the book?
This is one of those verbs you just have to memorize the particle it attaches to (に in this case). I believe there’s an explanation in a previous JFZ book or video (but I’m not sure since I study from many different sources) that suggests thinking about NARU as a direction for the thing you (or whoever/whatever) are becoming. I know it’s probably not the answer you were looking for, but hopefully it helps a little. Maybe someone else has a better explanation for it.