Southern Vietnamese Tones
Southern Vietnamese uses five tones. Two of the Northern tones — hỏi and ngã — merge into a single dipping-then-rising tone in the South, so where a Northern speaker hears six distinct tones, a Southern speaker hears five. The other tones (ngang, huyền, sắc, nặng) are present in both, with the Southern contours a little flatter and less sharply broken.
ngang (level, flat)
A flat, level pitch that stays steady — the "no mark" baseline tone.
huyền (low, falling)
Starts low and falls gently, like a quiet sigh.
sắc (high, rising)
Rises sharply to a high pitch.
hỏi (dipping, rising)
Dips down and then comes back up, like a questioning "huh?".
nặng (heavy, dropping)
Drops fast and heavy, cut short low in the voice.