One difference is the focus of Behavior therapy is usually first on breaking down the speech into functional components rather then structure of the words or sentences. Behaviorist usually set goals such as training of words to attain items, express a need or other functional use of the words. Speech therapist traditionally stress the formulation of the words and the exact pronunciation as well as use of the word. Note that the above is a generalization over many years of experience and observation and may not be the case with all speech therapy.
A second major difference is the focus of the behaviorist is on generalization, maintenance of speech and using the words in the environment on a daily basis consistently. In order to achieve this behaviorist typically set up different environments to practice the functional use of the words at home or on outings for example. The may also have the client use the words throughly the day in different situations in one environment in order to achieve consistency. Behaviorist almost always set-up contingencies and reinforcers specific to the individual in order to motivate the client to actually Speak. The outcome research and applied application usually shows a tremendous increase in verbalizations by the client in a very short time using Behavioral Approaches.