・ Attempting to pronounce "ha" sounds
First of all, pronounce "ka-ki-ku-ke-ko." Let the central back of the tongue come into contact with the hard palate (the innermost part of the upper jaw) to narrow the space between (point of articulation), and apply abdominal pressure to raise the intraesophageal pressure. Check to make sure that the "ka" sound is actually produced.
Next, further narrow this space by letting the deeper site of the base of the tongue come into contact with the hard palate. At the same time, fully apply abdominal pressure, and forcefully expel air. At this time, care must be taken to avoid oral whispering and also to prevent air from bursting from the tracheostoma.
At the same time, produce the sounds of "haa" and "hii" by shaping the mouth to produce "a" and "i".
・ Exercise
This is where deep abdominal pressure is of the greatest help in pronunciation. Increase intraesophageal pressure as far as possible to cause air to burst at one stroke through the new glottis . Prepare the mouth for the shape "a" immediately before breathing out.