Suppressed air from the lower parts of the lungs moves on freely to the mouthpiece just like a river flow. Its only “barrier” is the tongue which, with its top side, (a bit over the top) lies soft on a mouthpiece.
We make the initial tone (attack) with a small separation of the tongue (“barrier”) from the mouthpiece, in order to get (pour) the air flow through it. At the same time, we pronounce the syllable ta softly (we simply insert it into the mouthpiece) and it may also be pronounced tu, to, ti, te – depending on the country and its schools. Reedy tab vibrates and creates a tone. The tone must be clear, bright and pleasing to the ear.
Taken from my book