Most of us have heard plenty of examples of the so-called Intrusive-R. It is a feature of non-rhotic dialects, including British RP and some New England dialects. It occurs between two vowels that are normally articulated, such as a vowel ending one word followed immediately by a vowel beginning another word, presumably to avoid having to produce a glottal (or other) stop. Or, according to Wikipedia:
The phenomenon of intrusive R is an overgeneralizing reinterpretation of linking R into an r-insertion rule that affects any word that ends in the non-high vowels /ə/, /ɪə/, /ɑː/, or /ɔː/; when such a word is closely followed by another word beginning in a vowel sound, an /r/ is inserted between them, even when no final /r/ was historically present. For example, the phrase bacteria in it would be pronounced /bækˈtɪəriərˌɪnɪt/. The epenthetic /r/ can be inserted to prevent hiatus, two consecutive vowel sounds
That passage goes on to note one of the more famous examples, which occurs in the second verse of The Beatles' song "A Day in the Life" as John Lennon sings:
I saw[r]a film today oh boy
The English Army had just won the war
Instances of this phenomenon are legion and, as far as I am aware, uncontroversial. Nevertheless, I have recently noted instances, in the speech of a woman I know, of what can only be called Intrusive-L, because it occurs in the same place and under the same circumstances as Intrusive-R.
For example, the other day she described her children, as she watched them on an amusement park ride, like this:
And I saw[l]'em waving at me as they went by.
Now, she could merely have said "saw them" instead of trying to produce "saw 'em" and the problem would have been obviated, but that's not what happened. There have been other instances as well. Note that she never mixes up /r/ and /l/ in speech, as some people do. She grew up in Southern California, by the way.
My question is this: Is this merely the product of her own idiolect, or is Intrusive-L actually a recognized feature of some dialect(s)?
Note: I went looking for it, but searches for Intrusive-L all seem to assume I really mean Intrusive-R and only return articles about that well-known feature.
Based on the evidence in Araucaria's excellent answer I pursued the matter a bit further, contacting the woman and asking her if other family members produced the same intrusive-l sound in everyday speech. She said her mother and grandmother both do. And where is that branch of the family from? Why, Pennsylvania just west of Philadelphia.