As an expat with only a passing understanding of Cantonese, I always find the local cha chaan tengs daunting. When I first landed in Hong Kong, the job I had lined up fell through so I ended up working in a little kindergarten in Yau Ma Tei. It was surrounded by all the amazing little restaurants in Mong Kok, but I never set foot in one, as there was a McDonald's next door and it was less scary to just go there. Then one day, after learning the cantonese for sweet and sour pork - gou lo yot - I plucked up the courage to go in to a local eatery. It was a disaster! I ended up with some rice and vegetables by pointing at the wall posters.
I've been in Hong Kong and Tung Chung for 7 years now and I still get a bit nervous about going full local, but that's a BIG mistake, as that's where the best, and cheapest food is.
If you're hungry, I implore you to head to the new chinese cha chaan teng where Kimos used to be. The food is just so good. Head there for breakfast and you can expect the usual noodles with satay beef, or ham with macaroni and an omelette. All for about $40. They're nice, but there is only so nice you can make macaroni.
I suggest you head there for lunch or dinner and try their bbq pork - tsar sui - with either noodles - mein - or rice - fan - and vegetables - choi.
Or go for the sweet and sour pork - gou lo yot -, but be warned as the portion is enough to fill a hungry hippo. Don't fancy that? Hit up the fried beef noodles - gon tau nau hor. Wash it all down with a local milk tea - yeet nai ta - or iced lemon tea - dong leng ta. We fed a family of four with drinks for $200 and we were stuffed. It really is very good and a welcome change from the usual burgers and pizzas.