- a series of changes in the quality of the long vowels between Middle and Modern English as a result of which all were raised, while the high vowels (ē) and (o̅o̅), already at the upper limit, underwent breaking to become the diphthongs (ī) and (ou).
- a phonetic change that took place during the transition from Middle to Modern English, whereby the long vowels were raised: (eː became iː, oː became uː), etc. The vowels (iː) and (uː) underwent breaking and became the diphthongs (aɪ) and (aʊ)
