The big difference is the way they pronounce words. There is no standard, like British and American English, you speak in one accent, everyone will understand.

It's also how Northern and Southern people use different words to describe the same thing. E.g: car => Northern: ô tô Southern: xe hơi bowl => Northern: bát Southern: chén dirty => Northern: bẩn Southern: dơ ... and so on. You can google this and see there's a list of different words :) I hope this helps!

Ha Noi ( in the north) is the locality has a voice near the "standard language" most. Southern people say the following: - About tone: tilde and questions marks. The same is read as a questions marks. - For the first consonant: + The consonant / v / is replaced with / w /. For example: văn hóa → văng woá, vá → já, vệ quốc → vệ wók, v.v... + the Buffer Sound /-w-/ is slowly disappearing. For example: luật → lục, toàn → tàu, nuốt → núc, v.v... - About the rhyme: + Uniform rhymes: /–in/ or /–ít/ → /–inh/ or /–ích/ => For example: tin → tinh, mít → mích, thìn → thình, thịt → thịch, v.v... + The rhyme: /–un/ or /–út/ → /–ung/ or /–úc/ => For example: bún → búng, cùn → cùng, (một) chút → (một) chúc, nút → núc, bùn → bùng, v.v... + Some typical rhymes in the South of Viet Nam such as: * The rhyme: /–ênh/ → /–inh/ => For example: bệnh → bịnh, lệnh → lịnh, kênh → kinh, v.v... *The rhyme: /–inh/ → /–anh/ => For example: chính (sách) → chánh (sách), chính (quyền) → chánh (quyền), (hành) chính → (hành) chánh, v.v... * The rhyme: /–ân/ → /–ơn/ => For example: nhân → nhơn, nhân (quyền) → nhơn (quyền), nhân (ái) → nhơn (ái), v.v... * The rhyme: /–ing/ → /iêng/ => For example: kính → kiếng, v.v... <Sorry, because I'm not good at English.>

I think the big difference is pronunciation. For example, the letters "d" and "gi", "tr" and "ch", or even "r" and "gi" are read the same in standard Vietnamese but they are totally different if you hear a Southerner read them. About the tone, in standard Vietnamese, "dấu hỏi" and "dấu ngã" are read totally different but the same in Southern ones. I suggest you should hear the two dialect to distinguish them easily. P.s: Sorry for my bad English.