Not just use Eng & PTH to present. That the daily languages in the school, at least with the teachers. Like yesterday my daughter left her swimming bag on the school bus, she had to ask the teacher to help her to get it back. So they got no choice but to speak in either Eng or PTH. But you cannot expect them to speak Eng like native, as most of their classmates are local Chinese. They still like to talk with each other in Cantonese.