As per information from the U.S. Department of State, translators responsible for generating certified English translations don't necessarily need to possess official certifications. However, they must be proficient in both Vietnamese and English. The translation should be accompanied by a statement from the translator attesting to their proficiency in both languages and the accuracy of the translation.

Based on directives from the U.S. Department of State, every translated document should be appended with a signed statement from the translator, certifying their fluency in both Vietnamese and English and the accuracy of the translation. It should be noted that Vietnam is not a signatory to the Hague Apostille Convention, so an apostille may not be applicable. Instead, Vietnamese nationals may need certain documents to be notarized or further authenticated. 

It is advised for Vietnamese nationals to directly engage with the U.S. Embassy and Consulate in Vietnam to get precise and up-to-date requirements specific to their individual circumstances.