-igh words

Words that now have an -igh, like light and high, descend from two groups of Middle English words, distinguished by the length of the vowel. The chart below separates the original two groups by row:

Middle English sound

ME spelling

Mod English sound

ModE spelling

[i:ç]

high
sighen

[aɪ]

 

 

[aɪ]

high
sigh

 

knight
right

[ɪç]

cnight
right

 

The voiceless palatal fricative [ç], which can be heard in German ich, is made by raising the middle of the tongue to the hard palate. It is distinct from the voiceless velar fricative [x], as heard in the Scots dialect pronunciation of loch; [x] is sounded farther back in the throat.

In these examples, when the [ç] was lost, the preceding vowel, if short, was lengthened.