I live in a road called Poplar Road. You wouldn’t believe how often people misspell the name of the road as “Popular”.
Poplar is pronounced ˈpɒplə. Popular is ˈpɒpjʊlə or more casually ˈpɒpjələ, and as far as I know it is not normally compressed to a bisyllabic form (except perhaps in Norfolk or south Wales). On the other hand city dwellers may be astoundingly ignorant about the names of trees and other plants, and some perhaps don’t know that a poplar is a kind of tree. So they hear this unfamiliar word as the familiar popular.
Our road was once graced by a row of tall and stately poplars. Sadly, the last one remaining was felled a few years ago.
Here’s an exchange on Facebook that was picked up by the icanhascheezburger site.
Another word in which people often epenthesize an extra vowel is athlete. The standard pronunciation, following the spelling, is ˈæθliːt. But an awful lot of speakers break up the medial consonants with a schwa, thus ˈæθəliːt. In LPD I give this version a warning triangle.
The same applies to athletics, triathlon, etc. And people then spell them wrong, too.
Just yesterday I heard a television newsreader announce a breakthrough in the treatment of ˌɑːθəˈraɪtɪs (arthritis). I’ve given that one a warning triangle in LPD, too.
Why do medial θl, θr present a problem? There are plenty of cases where we have these sequences across a morpheme or word boundary: heathland, both lanes, hearthrug, death report and so on, and for AmE with love, with respect etc. And θr is a perfectly ordinary initial cluster: three, thrust, through. No one finds it necessary to apply svarabhakti / anaptyxis / epenthesis in these cases, so why in athlete and arthritis?