My English teacher grew up in Texas and unsurprisingly her native dialect is Texan English. I noticed that when intervocalic /l/ is followed by /i/, the /l/ is elided and /y/ takes its place. For example, "million" is pronounced "miyyon" and "bill you" is pronounced "biyyou". I wanted to see if this feature was also present in SAE, as it could explain the origin. Texan English seems to derive a lot of features from SAE.
According to Wikipedia, l-vocalization is any case where /l/ becomes a vowel or semivowel. However, most examples that come up when I try to find information on "English l-vocalization" are cases where dark l is elided or replace with /w/. So, either the feature in my teacher's dialect is not actually an example of l-vocalization, or I'm just terrible at using google.
So, my question is this: Is the /l/ to /y/ feature derived from SAE? If it is, where could I find more information on this sort of topic in the future?