Speech Therapy is a field of expertise practiced by a clinician known as a speech-language pathologist (SLP), also called speech and language therapist, or speech therapist, who specializes in the evaluation and treatment of communication disorders, voice disorders, and swallowing disorders. In other words, the speech-language pathologist is the professional who engages in clinical services, prevention, advocacy, education, administration, and research in the areas of communication and swallowing across the life span from infancy through geriatrics.