Complex sentence: Skinner's account takes verbal behavior beyond an intraindividual process to an interindividual process of particular interest is that he even defined verbal behavior as "behavior reinforced through the mediation of others".
Split into simpler sentences: Skinner's account takes verbal behavior beyond an intra-individual process to an inter-individual process. Of particular interest is that he even defined verbal behavior as "behavior reinforced through the mediation of others".