How do I play vibrato on ocarina?
Playing vibrato on the ocarina is accomplished by varying your breath pressure.
To learn how to play vibrato, it is best to start by practising exhaling at different rates. At first, do this without your ocarina. With a large aperture between your lips to create a bit of resistance. take a deep inhalation from the diaphragm and exhale as rapidly as you can. Secondly, do the same thing but exhale more slowly. Practise both of these alternately until they become natural; you may find it helpful to put your hand on your belly. Finally, vary your breath pressure as you exhale. These three exercises are demonstrated in the video below.
Ocarinas are unusual in that the pitch of their high notes is much less sensitive to pressure changes than the low notes. I recommend that you begin working on your vibrato using notes in the middle of the range. Focus on making the fluctuation of your vibrato consistent over time. This gets easier as it enters your muscle memory. It is helpful to practise to a metronome. Start slowly (between 40 or 60 BPM), placing the peak of your exhalation on the beat.
The pitch change should not be excessive; a fluctuation of 10 to 20 cents is fine as a starting point. As you get better, you can begin to increase the tempo with your metronome. When the frequency of your vibrato is slower, you will want a larger change of pitch, reducing it as the rate of your vibrato increases. You should also practise on lower and higher notes. Notes higher in the scale require a considerably larger pressure change to achieve the same effect.