The core concept of this question is to test the understanding of vocabulary related to communication skills. The correct answer is 'articulate' because it means to express an idea or fact clearly and effectively. 'Accumulate' means to gather or collect something over time, 'apparent' refers to something that is easily seen or understood, but does not relate to communication, and 'adopt' means to take on something new. Therefore, options A, C, and D do not fit the context of clear and understandable communication.