The problem we have understanding Ozzie Osbourne in this TV ad has nothing to do with his pronunciation.
Standard American English differs from the British variety, but no one has any trouble understanding Bono, Queen Elizabeth, or the Geico lizard. Ozzie is unintelligible in this ad because he fails to enunciate. All his consonants and vowels run together in an undifferentiated blur of sound.
pronunciation: The action of pronouncing a word or words; the way in which a word is pronounced, esp. with reference to a recognized standard.
enunciation: The uttering or pronouncing of articulate sounds; manner of utterance.
President Bush was ridiculed for his pronunciation of the word nuclear. Many “grammar nazi” type blogs wax sarcastic about the “only acceptable” pronunciation of such words as almond, herb, and February, but generally speaking, standard American English is accepting of a wide variety of regional accents and pronunciations.
Spoken language is fluid. Pronunciations change from generation to generation. Individual speakers don’t even pronounce some words the same way all of the time. A great many pronunciations once considered to be incorrect have acquired wide use as alternate pronunciations. Two examples are the words vehicle and often. Start paying attention and you will notice that some speakers pronounce the h in vehicle and some don’t. Likewise, some speakers pronounce the t in often and some don’t. Not so many years ago, sounding the h and the t in those words was considered non-standard. Now both pronunciations are regarded as acceptable standard variants.
Only disrespectful, inconsiderate people make an issue of other people’s pronunciation in everyday conversation. On the other hand, speakers who respect their listeners make an effort to be understood.
Vowels are the biggest culprits when it comes to regional variations that can cause confusion.
For example, some Southern dialects make so little distinction between the sounds of e and i that confusion can arise with such words as pin and pen. The tendency to lengthen vowel sounds–another characteristic of Southern speech–can also lead to misunderstanding. For example, between words like shell and shale.
Some East Coast speakers pronounce the o in dog, and coffee with the sound it has in God and mop. Some pronounce the word tourist as if the tour- had the sound of tore. According to an article on eHow, speakers from Philadelphia may pronounce Eagles as “iggles” and beagle as “biggle.”
Regional accents add color to language, but if you find yourself having to repeat yourself frequently when speaking with strangers, you may want to pay some attention to your enunciation.

