طرف اللسان وأصول الثنايا
The tip presses against the roots of the upper front teeth — where the tooth enters the gum — and cuts the air off. Ṭāʾ, dāl and tāʾ are all made exactly here.
Letters made here
Common mistake
Making them where English does, on the ridge behind the teeth. Arabic sits further forward, on the teeth themselves.