How does the shape of the lips and the movement of the mouth affect speech production?

The shape of the lips and the movement of the mouth play a crucial role in speech production. Different lip shapes and mouth movements help create specific sounds by controlling the flow of air and shaping the vocal tract. For example, rounding the lips for sounds like "o" and "u" or spreading them for sounds like "a" and "i" can change the quality of the sound produced. Additionally, movements of the tongue and jaw in coordination with the lips further refine the sounds we produce during speech.