Trisyllabic laxing, or trisyllabic shortening, is any of three processes in English in which tense vowels (long vowels or diphthongs) become lax (short monophthongs) if they are followed by two or more syllables, at least the first of which is unstressed, for example, grateful vs gratitude, pronounce vs pronunciation. By a different process, laxing is also found in disyllabic and monosyllabic words, for example, shade vs shadow, lose vs lost.
