Comment by CapsAdmin

Aha, so in the case of Bắc Ninh, its English name is the same as it is in Vietnamese; with diacritics.

I was going to say Da Nang and Ho Chi Minh City have gotten english names indirectly due to their popularity or relevance in Vietnam, but the main capital of Vietnam, Hà Nội, has the same problem as Bắc Ninh where its English name is the same as the Vietnamese name.

I guess there's no logical reason behind this, as this sort of data is likely crowd sourced.