Shin Tokuma tells me he was listening to BBC R4 as he drove along. He thought he heard people talking about a “Simon Cow”, but then realized it was actually “Simon Cowell”. How could his confusion have arisen? he asks.
Being a NNS, he was inclined to blame his poor listening skills, but (knowing his ability as a former UCL student) I don’t think he has any reason to blame himself. Cow and Cowell can sound very similar in some English people’s speech.
OK, Cowell is basically ˈkaʊəl. But (1) the diphthong plus schwa sequence might be subject to smoothing and compression, and/or (2) the schwa might be swallowed up in the final dark [ɫ], which in turn (3) might become vocalized.
(1) Smoothing is what turns aʊ.ə into a.ə, as when power is pronounced as ˈpa.ə. Compression makes this one syllable rather than two, paə, often also making the result a monophthong, paː, pɑː. This may make power a homophone of par, pa. So Cowell can be kaəɫ, kaːɫ and is a potential homophone of Carl kɑːɫ.
(2) Many (most?) English people make vowel rhyme with owl, towel with foul. That is, we have lost the distinction between aʊə and aʊ in the environment of a following ɫ. So Cowell is generally a homophone of cowl.
(3) With L vocalization, widespread in southeastern England, there is no alveolar contact for the segment and the older ɫ turns into a back, usually rounded, vocoid, conventionally written o. The only difference between cow and cowl, Cowell is then that the latter may have a somewhat different timing in the tongue movement, greater overall duration, or a slightly different target for the end of the resultant diphthong. Compare the similar vow - vowel, boughs - bowels. If there is a difference, it may well be one of those intriguing cases where the speaker believes he is making a difference but the hearer can’t perceive it reliably.
Particularly in noisy conditions, as when Shin was listening to his car radio.