Introduction: The book in your hand is an effort to explore possibilities to provide for interaction which is one of the basic needs of human for living in a social community. Communication in any form is known as the most important channel for social interaction that happens all the time. Interpersonal communication is one form of communication process that does not take place all the time, but it emerges in collective relations such as discussions, business, classroom, etc. (Wood, 2010). Different people react differently to similar actions, events or situation in their social relations (Allport, 1937, cited in Mischel, 1986). They employ different approaches toward interaction to people, answering the questions and overcoming the problems and challenges. When two people use different kinds of communication tools and skills to convey meaning, the process of interpersonal communication happens. Interpersonal communication is “a goal-driven interaction between at least two people that typically occurs in a face-to-face environment”(Long &Vaughan, 2012, p.1). This matter is significant in language learning since the ultimate purpose of learning a language is communication. Based on the difference in personality nature of individuals, they act differently in different communication situations. Therefore, interpersonal communication can be studied as a subject in the area of individual differences.

Keyword: Individual Differences, Personality, Traits, Assertiveness, Aggressiveness, Passiveness and Submissiveness, Assertiveness and Educational Setting, Foreign Empirical Studies, Domestic Empirical Studies, The Need for Vocabulary Instruction, Issues in Vocabulary Instruction, Cognitive Processes of Vocabulary Learning, Depth of processing model, Attention and noticing, Implicit and explicit learning, Incidental vs. Intentional Vocabulary Learning, Receptive vs. Productive Vocabulary