All speech sounds are made in this area. None are made outside of it (such as by stomping, hand clapping, snapping of fingers, farting, etc.)
Theoretically, any sound could be used as a speech sound provided the human vocal tract is capable of producing it and the human ear capable of hearing it. Actually only a few hundred different sounds or types of sounds occur in languages known to exist today, considerably fewer than the vocal tract is capable of producing.
Thus, all speech sounds result from air being somehow obstructed or modified within the vocal tract. This involves 3 processes working together: