ABSTRACT

This chapter presents the description of vowel variation, and describes other common and less common differences which operate independently of the basic vowel qualities. It explores vowel duration and clipping processes affecting this; direction of airflow; complexity, including monophthong/diphthong/triphthong, prominence, smoothing and compression, diphthongization and breaking; tongue root and tip gestures; fricativization and the effects of phonation types. Some languages use the duration of a vowel to change meaning. When a particular vowel quality is sustained for a short time, a particular meaning is understood, but when the same quality is used with a longer duration, the meaning changes. The length of a vowel is also affected by how many unstressed syllables follow. Smoothing is the technical term used to refer to the simplification of complex vowels into simpler or simple vowels by means of which triphthongs become diphthongs and diphthongs become monophthongs. This is one process that features in English speech.