This paper aimed at explaining the definition of phonology and exploring phonetic aspects in English. A continuous sequence of language sounds, sometimes an up and down sound, sometimes a short pause or a long pause, sometimes a loud or soft sound, and sometimes a stretching sound and a normal sound. The classification of this word in linguistics has always been a topic that has never been overlooked, since Aristotle's time until now, including in Indonesian linguistic studies, the problem has never been resolved. This occurs, because, firstly, each language has its own characteristics, and secondly, because the criteria used to classify the word can vary.