Differences in South Vietnamese Tones
mã is pronounced the same as mả, mid to low level tone, may rise again to mid level at end of sentence or if stressed. Voice moves from normal to tense voice

Vowels:
ă is pronounced as a
a is pronounced as a long a
â is pronounced as uh as in plus, an ɔ with unrounded lips (ʌ) or as e as in brother, a schwa (ə)
ơ is pronounced as a long ɨ (a high schwa ə or New Zealand i)
y is pronounced as i

Consonants:
North Vietnamese Pronunciation
b is an implosive b (ɓ or like ʔb)
ch is pronounced as ch or ty (IPA c)
ch at the end of a word is pronounced as k
d is pronounced as z
đ is an implosive d (ɗ or like ʔd)
gi is pronounced as z
kh is pronounced as kh as in loch or Bach (x)
nh is pronounced as ny as in canyon (ɲ)
nh at the end of a word is pronounced as ng as in sing (ŋ)
ph is pronounced as f
r is pronounced as z
th is pronounced as t with a puff of air (&tʰ)
tr is pronounced as ch or ty (IPA c)
x is pronounced as s

Differences in South Vietnamese Pronunciation
ch at the end of a word is pronounced as t
d is pronounced as y (IPA j)
g is pronounced as gh, a voiced kh (ɣ)
gi is pronounced as y (IPA j)
n at the end of a word is pronounced as ng as in sing (ŋ)
nh at the end of a word is pronounced as n
r is pronounced as r
s is pronounced as sh as in shop (ʃ)
tr is pronounced as retroflex ch
th at the end of a word is pronounced as k
v is pronounced as vy or y (IPA j)

Please note:
Words for "You"
Bạn means "friend" and is not often used. It is more usual to use these words:
Ông to a much older man, or to be formal (= grandfather).
OR Mr/Sir. (formal/general)
Bà to a much older woman, or to be formal. (= grandmother)
OR Mrs/Madam. (formal/general)
Bác to an older man or woman, less formal. (= senior aunt/uncle)
Chú to a man of an older generation, less formal. (= younger uncle)
Cô to a woman of an older generation, less formal. (= younger aunt)
OR Miss/Madam. (formal/general)
Anh to a man of your same generation. (= older brother)
Chị to a woman of your same generation. (= older sister)
Em to a young man or woman, very informal. (= younger sibling)
Con to a child. (= child)
These words can also refer to yourself, "I/me", instead of the general word tôi.