Acoustic Contrast · Scoop vs Cutoff
Both tones drop from mid-pitch, but their destination is completely opposite. Hỏi descends into a dip and scoops back up; Nặng plunges downward and stops dead with a firm glottal lock.
Acoustic Anatomy
The distinction lies in whether your vocal pitch recovers back upward or is abruptly terminated by vocal fold closure.
Thanh Hỏi (?) · Dipping Scoop
Contour: Three-stage curve: mid onset, low dip, and smooth upward recovery.
Sensation: Like an inquiring question in English ("Really?"). Continuous voicing with zero vocal break across the entire vowel duration.
Example: mả (tomb / grave)
Thanh Nặng (.) · Glottal Drop
Contour: Steep low drop cut short by a firm glottal closure.
Sensation: Truncated syllable (~250ms). Zero rebound upward—the sound stops dead in your throat like an abrupt catch.
Example: mạ (rice seedling)
Select minimal pair to test
Target Syllable
mả
Target: Dấu Hỏi (smooth dipping-rising scoop)
Contour Reference (Northern Standard)
Dip down smoothly and bounce the pitch back up, then record.
Speak clearly in a quiet room. We test duration, clipping, and background noise first so you never get fake feedback from bad audio.
Diagnostic Cue
Targeted Tone Training
Đúng Chưa? provides real-time signal checks and one focused cue per attempt so you build muscle memory on difficult tone pairs without score gamification.