Vocalisation of [r]

It occurred in the 16^th – 17^th c. Sound [r] became vocalised (changed to [ə] (schwa)) when stood after vowels at the end of the word.

Consequences:

• new diphthongs appeared: [εə], [iə], [uə];

• the vowels before [r] were lengthened (e.g. arm [a:m], for [fo:], etc.);

• triphthongs appeared: [aiə], [auə] (e.g. shower [‘∫auə], shire [‘∫aiə]).