People in general assume that in learning a foreign language, fluency is more important than accuracy. This view often urges language learners to think that perfecting sentence structure and comprehending vocabulary are more important than learning how native speakers articulate words, and leads them to generate errors in the articulation of the language's speech sounds. However, precision in pronouncing words is especially essential for language learners, and English, in terms of pronounciation, is the most difficult language to master. This book, therefore, studies English phonological errors produced by English language learners. To be specific, it analyzes the phonological errors made by English Department students of Petra Christian University with the six English consonantal sound that do not exist in Indonesian phonetics system; [v], [ ], [ð], [ ], [d ], and [t ], as the main focus. The analysis should be useful for further research in the area of articulatory phonetics, and should be essentially helpful for English language learners and teachers, especially those whose mother tongue are not English, to understand the basic mistakes in pronunciation.