I work at a bi-lingual immersion school right now, and it's like that for me with three of our Mandarin program kids. I know like 6 words/phrases of Chinese and none are related to my content. The Spanish-speaking kids I have covered, except for that one time when I had a brain fart and couldn't think of the word for nurse and kept thinking the German word instead.
I run everything through translate, but then back-translate it and tweak the original English until it comes out coherent and as precise as it gets. Even if the work has to be in English (kinda, it's not like that much music vocab is English), I always give them the instructions in Chinese so they at least know what's going on.
Yes to the picto-cards with words in both languages and gestural language goes a long way. I'm also careful about using the same language every time to ask for an action. Even when they don't know the individual words yet, they'll figure out with repetition what you need them to do.
In an emergency situation, there's always phone translator apps. Just be careful of FERPA issues with that or get an admin's okey-dokey first.