What is Verbal Behavior?
Verbal behavior is a function based approach to language and communication. The focus is on the function of what is being said, not the structure of what is said. Verbal behavior therapy uses this the principles of Applied Behavior Analysis to teach communication and language based on function.
Lets take a look at the four main verbal operants or functions of verbal behavior:
A mand is a request or demand. The person making the mand is motivated by something and they are requesting the thing they want. An example of this is saying "cookie" when you are hungry and want a cookie. Mands are unique as they are the only verbal operant where you are requesting your own reinforcement. As such, this is one of the first things we teach and strength for low verbal or non-verbal kids. Once you are able to request your wants and needs, it opens up a whole new world!
A tact is labeling or commenting on something you see. The person making the tact does so based on visual stimuli. An example of this is saying "cookie" when you see a cookie or saying "tall" when you see giraffe. Teaching tacts expands vocabulary by teaching new words and concepts.
Duplics are identically repeating something that was heard (or read or seen). This includes echoics (vocal imitation), mimetics (motor imitation of language such as ASL), and copying (copying written language). An example of an echoic is hearing someone say "cookie" and saying "cookie". Imitation is a vital skill for learning new words and is often one of the first things taught, but non-verbal motor imitation may be targeted first to teach a child how to imitate. It's much easy to teach someone to imitate clapping their hands as I can take their hands a show them, compared to teaching someone to imitate the word "ball".
This is a more advanced verbal operant which includes answering questions and having a conversation. Intraverbals are a response to someone else's verbal response, but unlike duplics the responses are not identical. An example of an intraverbal is hearing "What is a round, sweet, food with chocolate chips?" and responding "cookie". However, this can become much more complex and accounts for much of our social communication.
Notice that in all of these examples, the word "cookie" was used by the function of that word was different for each verbal operant. It's important to keep these functions in mind when teaching language and not to assume that teaching a word for one verbal operant will generalize to the others.