I feel like explaining the differences in the pronunciations of Northern and Southern Vietnamese. I myself am a southerner but am able to understand and of course mimic the dialect of the north (at least I feel I can).
The dialect for most of the teaching resources in and outside of Vietnam are done so in the northern dialect, which is considered the standard dialect as it is spoken by the inhabitants of the regions considered to be the birthplace of Vietnamese civilisation. In fact, the ethnic Vietnamese had been living in the northern parts of the modern day country for thousands of years and it wasn't until the 12th century onwards that a process of territorial expansion known as Nam Tiến
(Southward March). The south has just as many speakers (roughly 42 million each) and because of its growing importance in the economy, culture and media - the stigma of southern speech being an impure language is dying off (albeit slowly).
For a native Vietnamese speaker the difference seems very subtle and speakers from both sides are able to understand each other quite easily (especially since the local war ended). Ironically, both sides agree that the speech of the North-central and Central Vietnamese are somewhat bizarre and quite hard to understand for one unacquainted to them. However, for foreigners it's a different story. A foreigner will immediately hear 2 completely different languages at first mostly due to the differences in pronunciation and occasionally vocabulary.
(ND: Northern dialect, SD: Southern dialect)1. Tones
So what are the differences between the 2? First and foremost there are 6 tones in the ND whereas there are only 5 in the SD (2 tones have merged). The ND has all of the following: ngang (a), sắc (á), huyền (à), hỏi (ả), ngã and nặng (ạ) - whereas the south has merged both hỏi and ngã into the hỏi tone. Once you listen to a southerner speaking and the ngã tone, you'll probably agree that the ngã tone simply doesn't suit the SD.2. Consonants
Initial consonants are mostly the same except for d-, gi- and occasionally v- which are all pronounced /j/ in the SD but /z/ and /v/ respectively in the ND. The SD keeps tr-/ch- and s-/x- distinctive whereas the ND pronounce them as the latter in both. However, more and more SD speakers are doing the same nowadays. As for the final consonants, the SD has merged a lot of these! The following is a summary of the differences.Initial consonants
1. s-/x- and tr-/ch- are both distinct in the SD, but not in the ND
2. d-/gi- and occasionally v- are all pronounced /j/ in the SD and /z/ in the ND (except for v-)
3. qu- >/w/
4. kh- sometimes >/f/ or /h/ in informal speechFinal consonants
1. -c/-t > -c (except for -êt, -it)
2. -n/-ng > -n (except for -ên, -in)
3. -n/-nh > -n (in the case of -ên, -in only)
4. -ch > -t
5. -nh > -n3. Vowels
1. -â-/-ă- occasionally >-ă-
2. -ai/-ay occasionally >-ai
3. -ay/-ây occasionally >-ây
4. -ao/-au occasionally >-ao
5. -êu/-iu occasionally >-iu
6. -i- >-ư- before -ch, -n, -nh, -t
7. -iu/-iêu > -iu
8. -oa/oe pronounced like qua/que
9. 3-way merge between hoa/qua/oa all /wa/ etc.
10. -oi/-ôi occasionally >-oi
11. -ui/uôi occasionally >-ui
12. -ưu/-ươu occasionally >-u
13. -ưu and -ươu are distinct in the SD but become -iu in ND
In addition, r- has many pronunciations depending on the speaker in SD and can even become g- in informal speech plus more differences I haven't listed. As you can see southern speech can be quite difficult for a learner to grasp and even southerners sometimes have trouble remembering how to write words.
Here are a few samples of how the pronunciation is different.
1. Con chuột này có râu dài thòn.
[This mouse has a long moustache]
2. Cháu năm nay được mười tám tuổi.
[I am eighteen years old this year (from a young child to an old person)]
3. Hôm nay trời mát hơn hôm qua.
[Today is (was) cooler than yesterday]
4. Sôcôla bạn ăn hết rồi!
[You have eaten all the chocolate!]
5. Sẽ có một ngày tôi trở về!
[There will be a day when I will return!]
6. Tin tức đài số mười sẽ bắt đầu vào lúc 6 giờ và kết thúc vào 7 giờ tối.
[The channel ten news will begin at 6 pm and end at 7 pm.]
Using the northern spelling, the southern speech may be rendered as:
1. Coong chuộc nầy có râu dài thoòng
2. Cháo năm nai được mười tám tủi.
3. Hom nai trời mác hơng hom qua.
4. Sôcôla bạng ăng hớt rồi.
5. Sẻ có môọc ngài tôi trở về.
6. Tưn tức đài số mười sẻ bắc đầu vào lúc sáo giờ và kết thúc vào lúc 7 giờ.
I have made an audio clip but it's a .wav file so I can't attach it
> Northern sampleSouthern sample