Dấu Sắc (/) · High Rising
The Upward Climb
Contour: Starts at mid-pitch and sweeps cleanly upward to the top of your comfortable register.
Duration: Moderate-to-long duration (~250-300ms).
Example: cá (fish)
Acoustic Anatomy
Opposite Trajectories in Vocal Space
These two tones represent the maximum vertical dynamic range in Vietnamese phonology.
Dấu Nặng (.) · Heavy Drop
The Plunge & Glottal Cutoff
Contour: Drops precipitously from lower-mid to the bottom of chest register.
Duration: Extremely short (~150ms). Terminated abruptly by clamping vocal folds.
Example: cạ (close partner / card companion)
Select minimal pair to test
Target Syllable
cạ
Target: Dấu Nặng (short drop with glottal stop)
Contour Reference (Northern Standard)
Notice the short duration and abrupt stop, then record your attempt.
Recording check before feedback
Speak clearly in a quiet room. We test duration and volume first so you never receive fake scores from bad audio.
Your single correction cue
Drop pitch into lower chest register and cut the vowel off sharply.
Apply this single adjustment on your next attempt.
Curriculum Decks
High-Frequency Sắc vs Nặng Pairs
Contrasting rising vs falling glottal pairs eliminates essential misunderstandings.
| Pair | Sắc Word (Rising) | Nặng Word (Heavy Drop) | Key Diagnostic Cue |
|---|---|---|---|
| 1 | cá — Fish | cạ — Close friend / partner | Climb smoothly on cá; drop and clamp vocal folds short on cạ. |
| 2 | báo — Newspaper / Announce | bạo — Bold / Violent | Long rising sweep on báo; heavy abrupt drop on bạo. |
| 3 | má — Mother / Cheek | mạ — Young rice seedling | High vocal register on má; deep chest register cutoff on mạ. |
| 4 | chó — Dog | chọ — Cramped / crowded space | Bright high tone on chó; low damped decay on chọ. |
Regional Phonology
Regional Differences in Dấu Nặng
Northern Glottal Stop
In Hanoi, dấu nặng terminates with a true acoustic glottal stop—an instantaneous cut in the sound wave visible on any spectrogram.
Southern Breathy Decay
In Saigon, dấu nặng is short but softer, often transitioning with slight breathiness or creakiness rather than a harsh glottal lock.
Calibration Focus
For learners, the critical goal is preventing nặng from dragging out like a flat tone. Keep it low and short.
Take Practice Further
Practice Full Contrast Decks on Mobile
The mobile app provides full contrast decks, multi-syllable phrases, and sensorimotor trace calibration.