Speech-language pathology is the study of disorders that affect a person's speech, language, cognition, voice, swallowing (dysphagia) and the rehabilitative or corrective treatment of physical and/or cognitive deficits/disorders resulting in difficulty with communication and/or swallowing. Speech-language pathologists (SLPs) or Speech and Language. Therapists (SLTs) address people's speech production, vocal production, swallowing difficulties and language needs through speech therapy.