Trisyllabic laxing or trisyllabic shortening is a process in English whereby long diphthong sounds (said to be tense) become short monophthongs (lax) in word formation, normally in words of three syllables.
Examples:
- divine -> divinity /dɪ'vɪn.ɪ.ti/
- fragile /'frędʒ.aɪl/ -> fragility /frə'dʒɪl.ɪ.ti/
- nation /'neɪ.ʃən/ -> national /'nęʃənəl/
- private /'praɪ.vət/ -> privacy /'prɪv.ə.si/ (only in British English)
- ratio /ˈɹeɪ.ʃi.oʊ/ -> rational /ˈɹæʃ.ə.nəl/
