Originally Posted by GuitarBizarre

Tuna - The answer to your question is no. Deaf people occasionally have trouble speaking according to a certain model because they're unable to hear their own inflections.

As regards cultural variations on language - Thats irrelevant. Languages are constructed of a series of phonetic groupings and the interaction between those groupings leads to assimilation and appropriation of form by speakers of other languages or the bilingual over a period of time. Most if not all examples of regional accent while speaking a common language are examples of lingering cultural holdovers in pronunciation from previous dialects and cultures.

English is a particularly good example of this due to its mongrel nature, being comprised of hundreds of different languages all filtered through each other and various successions to create modern english. This is also why we have an unusually large spread of regional accents, compared to, say, Japanese, where there are only a limited number of regional dialects, which are currently in remission due to the greater standardisation of contemporary japanese, or hyōjungo.