This phonological analysis investigated the English vowel sounds as the central phenomena represented by letters descriptively and qualitatively. It was supported by the theories proposed by Finegan, Hayes, Kreidler, Skandera & Burleigh, Roach and Yule. The method of data collection was observational by identifying the English articulation. The articulatory phonetic identity method was used to analyze the data with competence in differentiating. The Oxford Advanced Learner’s Dictionary was used as a standard form of British pronunciation (Received Pronunciation) to compare the sounds produced and differentiate the English alphabet letters. Some patterns of English vowel pronunciation were found, i.e. <r> positioned as a close syllable lengthens [A:, O:, 3:] and produces schwa, and does so similarly in diphthong. Double semivowels do not perform triphthong. The letters i, u, w and y produce triphthong when they are combined with vowels.
Keywords: phonology, Received Pronunciation, vowels