What you are training
"Mah" is the most useful syllable in singing. The M starts the sound gently and forward, and the open "ah" is the vowel that resonates most freely, which is why it is the one singers reach for on high notes. Running a major scale on it teaches three things at once: a soft onset, an open throat, and pitch on the scale degrees that every melody is built from. It is also the exercise that exposes a tight jaw or a raised tongue, because both change the vowel on the way up. This exercise plays each step of the scale and listens for your match. Aim for the same "ah" on every note, top to bottom, rather than a bright "ah" low and a swallowed one high. Three minutes, and the vowel you sing with afterwards is noticeably rounder.
How to do it
- Sing "mah-mah-mah-mah-mah" up the 5-note scale.
- Drop the jaw on each "ah" - feel the openness.
- Move up by half step each round.
The "m" consonant places you in the resonance, and "ah" opens the throat. Together they build the bridge between placement and space.
After this exercise, the plan: The daily plan follows this with pure-vowel sustains, so the "ah" you find on the scale becomes the shape you hold on a long note.
If singing hurts, stop. Pain, hoarseness, extra effort, loss of range, or repeated throat clearing that lasts more than a day is a reason to see an ENT or laryngologist, or a speech-language pathologist who specializes in voice. It is not a reason to practice harder.