John Wells in a recent post dealt with some aspects of clear and dark /l/ in English. Rather than post a long comment, I thought I’d deal with some of my thoughts on the matter here.
First, it is clear (ho! ho!) that not all varieties of English have a pair of voiced alveolar laterals distinguished by the presence vs absence of velarisation. In Glasgow, for instance, /l/ tends to be velarised in all environments, while for many speakers in Ireland /l/ is usually non-velarised. I wonder, however, if even those accents that have both varieties (I suppose we could call them “bi-lateral”) there is a continuum of l-darkness. The thought is prompted by John Wells’s remark that the final /l/ in feel in the phrase feel ill is clear for him. It isn’t for me.
Fairly frequently, and especially in accounts for non-native speakers, one comes across statements like: if /l/ is followed by a vowel or /j/ it is clear, but elsewhere it is dark. This is a simplification of what really happens, I think. One needs also to consider whether a vowel following the /l/ is in the same word or not. In feeling, for example, the /l/ is clear, but so it is in the phrase feel it. But obviously speakers vary as to what they do in phrases like feel ill or tell Eric. Maybe some speakers (like me) are sensitive to the foot boundary between feel and ill, whereas the boundary is of no consequence to others, like John Wells for instance. There are probably other speakers who are sensitive to the word boundary in feel it.
I don’t remember seeing any discussion of this sort of thing in the literature.