Scottish Vowel Length Rule

The Scottish Vowel Length Rule, also known as Aitken's Law after Professor A.J. Aitken who formulated it, describes how vowel length in Scots and Scottish English is conditioned by environment.

The rule affects all vowels in Central dialects, while in peripheral dialects some vowels remain unaffected.


 * and are usually short.
 * and are usually long:
 * in stressed syllables before and.
 * before another vowel and
 * before a morpheme boundary.
 * , and  are usually long in most dialects.
 * The diphthong usually occurs in short environments and  in the long environments described above.

The Scottish Vowel Length Rule is assumed to have come into being between the early Middle Scots and late Middle Scots period.

Ley de Aitken