Weak vowel merger

The high and mid-height front vowels of English (vowels of i and e type) have undergone a variety of changes over time, often varying from dialect to dialect.

Middle English had a long close front vowel /iː/, and two long mid front vowels: the close-mid /eː/ and the open-mid /ɛː/. The three vowels generally correspond to the modern spellings ⟨i⟩, ⟨ee⟩ and ⟨ea⟩ respectively, although other spellings are also possible. The spellings that became established in Early Modern English are mostly still used today, although the qualities of the sounds have changed significantly.

These /iː/ and /eː/ generally corresponded to similar Old English vowels, while /ɛː/ came from Old English /æː/. For other possible histories, see English historical vowel correspondences. In particular, the long vowels sometimes arose from short vowels, via Middle English open syllable lengthening or other processes. For example, team comes from an originally long Old English vowel, while eat comes from an originally short vowel that underwent lengthening; the distinction between these two groups of words is still preserved in a few dialects, as noted in the following section.

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