Articulation involves making speech sounds by varying the breath and by using the lips, tongue, teeth, and palate. Certain conditions can cause mild to severe distortion of sounds. There is a sequence of sound development that has been devised based on age. At these age levels, speech may only be easily understood by people familiar with the child. Again, this sound development is based on average ages.
Language development is more complex.
A child may have the inability to understand language or express language or both. While language learning may proceed in a somewhat predictable order, there is some variation in the expression of language skills. If there is excessive delay in production of words and phrases or inability to participate in conversation, this may not indicate a long-term problem, but it should be investigated. This investigation can be done by a speech pathologist with the participation of a dentist. A speech pathologist is involved in assessing the structure and function of the mouth, jaw, pharynx, and larynx.