What is your mouth used for? Speaking and eating. Some people also use the mouth for breathing (but they are supposed to be using their nose for that!) When you have concerns regarding speech sound production, it is important to also assess the feeding skills of that person. When eating a person stimulates the orofacial muscles and this promotes the growth of the face. There is a reason that we start eating immediately upon being born. It is to help stimulate the orofacial muscles so that we can help prepare them for more other complex tasks such as speaking. In the same way, proper suction and chewing prevents dental alterations and difficulties when structures such as the lips and tongue are moving. This is fundamental in the production of speech sounds.
Feeding and Speech therapy - The role of orofacial development