What are some authoritative Vietnamese dictionaries? …and how do they disambiguate the two pronunciations of
<gia>? (Something with an English or Chinese gloss is preferred.)
Wikipedia on the Vietnamese Alphabet has this to say about
This causes some ambiguity with the diphthong ia/iê, for example gia could be either gi+a [za ~ ja] or gi+ia [ziə̯ ~ jiə̯]. If there is a tone mark the ambiguity is resolved: giá is gi+á and gía is gi+ía.