Some Definitions

Communication is the exchange of information, the sending and receiving of messages. It is a two-way interaction and requires participation of a sender and a receiver. A message is encoded, transmitted and decoded. Communication breakdowns can occur if either party has difficulty performing their role. If the sender does not speak clearly or intelligibly, his/her message may not be received. If the sender does not use language appropriately, in a meaningful way, the message may not be received. If the receiver has a hearing impairment, an oral/spoken message may not be received. If the receiver has difficulty understanding language, they may not be able to decode the message.

Language is a shared code or system that represents concepts and ideas through the use of arbitrary symbols. It is rule-governed and shared by a given community. Typically, we use oral and written language to communicate. Other types of language include sign language, Blissymbol communication and pic-syms.

Speech is a motor act. It is the production of sounds in meaningful combinations by the lips, tongue, teeth, palate, vocal cords, and lungs for communication.
 

A Speech-Language Pathologist (SLP) is a specialist in the assessment, treatment and prevention of communication disorders. In  the United States, a university degree at the Master's level is the recognized standard of education.

SLPs are employed in hospitals, schools, rehabilitation centers, government agencies, and private practice. Many SLPs are specialized and work with specific populations or disorders, such as child language, learning disabilities, developmental delays, autism, articulation/phonology, fluency, voice, swallowing, neurogenics, dementia, and acquired brain injury.