ASHA:

The American Speech-Language-Hearing Association is the professional, scientific, and credentialing association for speech-language pathologists, audiologists, and speech, language, and hearing scientists in the United States.

Audiologist:

A trained professional who measures hearing loss, can fit hearing aids, evaluates for balance disorders, and tests for auditory processing disorder.

CCC/SLP:

Certificate of Clinical Competence, a nationally recognized professional credential that represents a level of excellence in the field of Audiology (CCC-A) or Speech-Language Pathology (CCC-SLP). Those who have achieved the CCC-ASHA certification have voluntarily met rigorous academic and professional standards, typically going beyond the minimum requirements for state licensure.  They have the knowledge, skills, and expertise to provide high quality clinical services, and they actively engage in ongoing professional development to keep their certification current.

Speech Language Pathologist (SLP):

A specialist who evaluates and treats patients with communication and swallowing disorders in individuals of all ages. In the U.S., a speech-language pathologist is a person with their Master's Degree in Speech-Language Pathology who has also completed a "clinical fellowship year" in order to be eligible for state licensure and national certification by ASHA. By definition, a pathologist locates the source and cause of problems. A therapist works with clients to remedy problems.

Speech-Language Pathology Assistant (SLPA):

A person who may hold a Bachelor's Degree and works under an ASHA Certified Speech-Language Pathologist.

Speech Teachers:

Secondary classroom teachers who provide instruction in public speaking and debate

 Speech Therapist:

Some states in the U.S. use the term speech therapist as someone who does not have a Master's degree but may have educational certification to practice in the public schools. All speech language pathologists are speech therapists, but not all speech therapists are speech language pathologists.