Verbal Behavior (VB) Therapy is an intervention based on the science of Applied Behavior Analysis (ABA) which focuses solely on communication. This intervention was developed based on the work of B.F. Skinner. Skinner explained that language could be analyzed into a set of functional units, with each type of operant serving a different function. The operants are Echoics, Mands, Tacts, Intraverbals, Listener, Echoic, Imitation, Texual, Copying a Text, and Transcription. These components of language are necessary for effective verbal communication and should be the focus of intervention meant to teach language. The work of Skinner has been expanded upon by many researchers in the field. They have theorized that these components of language are necessary for complete understanding, generalization, and mastery of language.