Djokovic has different pronunciations in England and the US. In England, the beginning is pronounced like jock, while in the US it’s pronounced like joke. Here are two BBC commentators. First, Englishman Tim Henman:
Second, American Andy Roddick:
The American pronunciation conforms to a pattern I described in an article 25 years ago: in the stressed syllables of foreign loanwords, American English likes to use five ‘tense’ vowels for the five vowel letters of the alphabet: PALM for a, FACE for e, FLEECE for i, GOAT for o, GOOSE for u. This is why Americans use the vowel of GOAT (and of joke) in eg Kosovo, Nokia, Prokofiev, Sochi and Djokovic.
The English, on the other hand, have an extra vowel which Americans don’t have: their ‘short-lax’ LOT vowel. It’s the vowel that sounds so English in Harry Potter. Americans use the PALM vowel in such words, pronouncing the first syllable of Potter like the last syllable of grandpa. The English also use their LOT vowel in jock (which Americans rhyme with Bach).
This LOT vowel is also quite near to the Serbian o, which we can hear from native speakers of Serbian on the valuable Forvo site:
So, if we were evaluating the competing pronunciations of Djokovic in England and the US, we might conclude that it’s 15-love to England.
But it’s not quite that simple. Both the Americans and the English use the GOAT vowel in Novak. That is, Americans use the same vowel in Novak and Djokovic, while the English use different vowels. Serbian has the same vowel quality in the two names, so the English are being inconsistent in using different qualities. The English also get the vowel lengths the wrong way round, with long GOAT in Novak and short LOT in Djokovic: the Serbian o is short in Novak and long in Djokovic. (This can be heard particularly from the two male native speakers.)
Brits and Americans often find each other’s pronunciations of foreign words strange, even ‘wrong’. But the pronunciation of loanwords results from a combination of factors, including spelling pronunciation conventions and, crucially, the sound system of the borrowing dialect. It’s generally not a simple matter of linguistic expertise.
(Jock is an informal American word for an athlete, and Novak Djokovic is known for his jokey impressions of other players.)
My 1990 article discussed various possible reasons for the emergence of the American 5-vowel loanword strategy. One is the influence of Spanish, the best-known and most-used foreign language in the US. Another is the loss from the speech of many (perhaps most) Americans of a distinct THOUGHT vowel; for these speakers PALM, FACE, FLEECE, GOAT, GOOSE are arguably a distinct natural class within the AmE vowel system.
There are plenty of exceptions to the strategy. One is Federer (a long vowel in German), which ‘should’ get the tense FACE vowel, as in Mercedes, but which Americans typically say with the lax DRESS vowel. The similarity to the English word federal may be the reason.
If loanword pronunciations were driven only by phonetic considerations, then the SSB THOUGHT vowel would be a fair candidate for Djokovic. But it violates spelling conventions: a simple o in spelling is never pronounced with the THOUGHT vowel. As I discussed in a blog post here, this explains why the phonetically-appropriate THOUGHT vowel was a non-starter for English correspondents pronouncing Sochi. As with Djokovic, SSB speakers used their LOT vowel and Americans used their GOAT vowel in Sochi.
An amusing but hard-to-hear YouTube video shows Novak Djokovic giving advice on the pronunciation of his name to American tennis-champion-turned-commentator Jim Courier. The two men are at cross purposes: Courier, if I hear right, wants to know whether he should use his GOAT or his PALM vowel in the first syllable, while Djokovic wants to talk about the initial consonant [dʑ], written Đ or Ђ in Serbian – another non-starter for English speakers.