This study provides an acoustic phonetic analysis of some of the vowels in an endangered language with little phonetic documentation, Scottish Gaelic.
It tests previous mainly impressionistic analyses which claim Scottish Gaelic has phonemic vowel length, and contrasts four high back vowels /u  o /. Results suggest four vowels are indeed contrasted, and that phonemic /u/ is divided into
two phonetically distinct allophones. Phonemic vowel length is robustly maintained, but younger and older speakers differ in some areas for vowel quality: for younger speakers one allophone of /u/ is moving closer to /i/, and the other allophone of
/u/ has merged with /o/.