"The day after tomorrow, they will have a discussion about Dutch culture."
Translation:Vào ngày mốt, họ sẽ thảo luận về văn hoá Hà Lan.
I'm sorry, it was a comment over 7 month ago. I've never used "ngày kia" as the day after tomorrow, and it was my first time coming across it as well. instead I've always said "hôm kia" and "ngày mốt", respectively the day before yesterday and the day after tomorrow.
that being said, I've asked my parents since then. my dad, who is a northern native speaker, was rather surprised when hearing about it. to be fair, he moved to the South in 1954, and we live abroad for over 35 yrs. my mom, who is a central native speaker, knew "ngày kia" being the day after tomorrow but I don't recall ever hear her say so. they both always use "ngày mốt".
I think they got a dialect mistake here. The day after tomorrow in Vietnamesse language means "ngày kia" or "ngày mốt", depends on regional dialects. In Northern Vietnam, they usually use "ngày kia", but "ngày mốt" is more frequently in Southern. So, I think we should have an additional answer for this question
Why do you translate 'thảo luận' as 'have a discussion' (verb+article+noun)? It is obviously the verb 'to discuss'. This sentence translates directly as, 'Tomorrow, they will discuss about the culture of The Netherlands/Holland.' It seems strange to translate the verb indirectly as a noun.