We present a new method for measuring the “darkness” of /l/, and use it to investigate the variation of English /l/ in a large speech corpus that is automatically aligned with phones predicted from an orthographic transcript. We found a correlation between the rime duration and /l/-darkness for syllable-final /l/, but no correlation between /l/ duration and darkness for syllable-initial /l/. The data showed a clear difference between clear and dark /l/ in English, and also showed that syllable-final /l/ was less dark preceding an unstressed vowel than preceding a consonant or a word boundary.
Bibliographic reference. Yuan, Jiahong / Liberman, Mark (2009): "Investigating /l/ variation in English through forced alignment", In INTERSPEECH-2009, 2215-2218.