A speech-language pathologist (SLP), also known as a speech therapist, is a health professional who diagnoses and treats communication and swallowing problems. They work with both children and adults of all ages in clinics, schools, and hospitals. They can help if you or someone you love has a developmental disorder, neurological condition, or brain injury that affects your ability to communicate with other people. They also can help if you have trouble eating or drinking safely due to swallowing issues.