vi) The teeth (upper and lower) are usually shown in diagrams like Fig. 1 only at the
front of the mouth, immediately behind the lips. This is for the sake of a simple
diagram, and you should remember that most speakers have teeth to the sides of
their mouths, back almost to the soft palate. The tongue is in contact with the
upper side teeth for most speech sounds. Sounds made with the tongue touching
the front teeth, such as English θ, ð, are called dental.