- Vowels are speech sounds produced with an open vocal tract, without obstruction of air flow, and are classified based on tongue height, frontness/backness, and lip rounding.
- The document discusses the classification of English vowels, including short vowels, long vowels, diphthongs, and triphthongs. It provides phonetic transcriptions and examples of words containing each vowel type.
- Vowels are contrasted with consonants, which involve closure or constriction in the vocal tract, obstructing air flow. The complex English vowel system and unpredictable spelling are also noted.