Tones in the Southern dialect (Saigon a.k.a. HCM city) behave quite differently from the standard tones.
Regarding tones in the Southern dialect, the good news is that there is no glottal stops. Another good news is that there are only five distinct tones in speech instead of six. However, the bad news is that more than half of the tones have a rising pitch, which means we can only differentiate between them based on their height.
Six basic tones
In speech, the Southern dialect only has five distinct tones because the second and fifth tones are pronounced the same.
First tone and fourth tone
The first and fourth tones in the Southern dialect are the same as their standard versions, there is nothing much to say.
Second tone and fifth tone
The second and fifth tones are pronounced the same in the Southern dialect: start with middle pitch and rise to high pitch. They are very similar to the standard third tone.
Third tone
The third tone is very high in the Southern dialect. It is so high that it goes beyond the normal five-level scale. There is a slight rise in pitch.
Sixth tone
The sixth tone starts with mid-low pitch and rises to middle pitch.
All-in-one tone chart
Checked tones
The checked tones are the same as their standard versions. Remember that the thing about checked tones is their height, not pitch contour, so only highs and lows matter.