Final answer:
Speech disorders are the cause of abnormal phonetic deviations that affect the production of speech sounds, often treated by speech-language pathologists.
Step-by-step explanation:
Speech disorders create abnormal phonetic deviations. Abnormal phonetic deviations refer to unusual changes or errors in the production of speech sounds. These deviations can be caused by a variety of factors, including developmental disorders, neurological issues, physical impairments, or hearing loss. For example, a child with a speech disorder may substitute, omit, add, or distort sounds, which can affect intelligibility. Speech-language pathologists are professionals who assess and treat speech disorders to help individuals improve their speech clarity and communication abilities.