In the Bristol area, a terminal “a” (realised as [aw], c.f. Albert as “Awbert”, cinema as “cinemaw”) is often perceived to be followed by an intrusive “l”. Hence the old joke about the three Bristolian sisters Evil, Idle and Normal — i.e., Eva, Ida, and Norma. Also the name “Bristol” itself (originally Bridgestowe, variously spelt).
I wrote then, “Unfortunately, as the Masters of Wiki say in a box at the top of the page, ‘This does not cite its references or sources,’ and I imagine it is not devoid of misstatements”; now, thanks to Paul (thanks, Paul!), I can present an essay by the linguist Chi Luu that opens with the same joke about “Evil,” “Idle,” and “Normal” and proceeds to discuss the topic with actual references (and links to audio clips):
The local Bristolian accent is notorious for a linguistic quirk known as intrusive-l, where some speakers seem unable to help themselves from adding a so-called dark “l” to syllables and words ending in certain neutral vowels—even going so far as to change the historical name of their city. It’s been suggested that appending an “l” at the end of a syllable was seen as more “correct” and thus started appearing in all sorts of places as speakers overcompensated, hypercorrecting words that never had an “l” to begin with.
Words like “areal” (area), “ideal” (idea), “pianol” (piano), “drawling” (drawing) and even the odd “bananal” (banana) have been noted. “Mango” becomes a homophone of “mangle” and “tango” sounds just like “tangle”. Check out this recording from the British Library Sounds collection for a few examples […]
To many, this might seem ever so slightly weird. Why add an “l” so randomly? […] Though it may be a little difficult to detect consistently, on the whole, there’s a well-documented sound change happening here. Once as a humble research assistant, I spent a summer cooped up in a dark room listening to countless strangers repeat words containing a syllable-final “l”, such as “milk” (which can sound more like “miwk”), “palm” (“paam”), “children” (“chiwdren”), “bottle” (“bottu”) and “cool” (“coo”). These words all contain just the right environment for the “l” to be replaced by some pod-person in the form of a vowelish sound that most people might still hear as an “l”. You may even be doing it yourself. Surprisingly, it’s found virtually everywhere…and it’s spreading. Sociolinguistic studies have shown that this emerging sound change, called l-vocalization, is widespread in dialects of English, from regions across the UK, Australia, New Zealand and yes, even the US, where it’s been observed all over, from California to Appalachia to Pennsylvania.
[…] But increasingly, l-vocalization is moving unnoticed into standard dialects of English, including British Received Pronunciation (RP), such that John Wells, an expert on accents of English, predicts that “it seems likely that it will become entirely standard in English over the course of the next century.”
She goes on to do an equally good job with intrusive-r; I recommend the whole thing.