In the speech therapy community (researched based) blocking on a word is classified as a type of stutter-like dysfluency. It is an interruption is speech the same as a repetition or prolongation. Blocking is also not a learned behavior just as prolongations and repetitions are not learned behaviors. In general stuttering is not a learned behavior. Blocking on a word or sound is not classified as an avoidance behavior, it is a dysfluency. There are techniques and secondary behaviors where the person who stutters may pause before speaking or between words. This is different than blocking. Blocking is characterized by the speaker having muscle tension with a fixed oral posture. Blocking is a struggle. A pause is not.