There are many differences among world Englishes. The most obvious is that between native and non-native speakers. Because English is such a common second language, oral communication in English is often shaped by sonic and syntactic patters of first languages, such as the pitch variations in Indian English or the tendency of east Asian English speakers to drop articles. Another major difference is what is sometimes called "contrastive rhetoric", the difference in social conventions and their linguistic representations. For example, Canadian speech reflects an English politeness tradition, while Australians tend to be blunter, and Arabic politeness requires more indirectness.
In pronunciation, look for differences in pitch (especially patterns of pitch variation), stress (British-influenced speech stresses syllables towards the beginning of the word, US-influenced English stresses syllables towards the end), pronunciation, and tempo as well as vocabulary differences.