This place only serves phở and bùn bò Huế [Huế beef noodles], so it is a Vietnamese restaurant. None of the waitresses speaks Vietnamese, however, and neither does the cook, or they would have appealed to him for help when I spoke Vietnamese. The bowl of phở I had this morning was excellent, so these people know what they're doing.

Update: on a second visit, I spotted a woman who appeared to be the owner talking to the cook in Vietnamese, so this is a Vietnamese owned restaurant.