English is a language with many ways to pronounce things. Pronunciation changes both through history and from dialect to dialect. Mostly, however, English has a mostly similar phonological system throughout the world. Most dialects are different from one another because they have different types of stress in syllables. Stops, affricates, and fricatives are also changed in consonants in different dialects.

There is also lots of research done on prestige(more formal) or standard(more common). These can mean Received Pronunciation for England, General American for the United States and General Australian for Australia.

Many dialects will grow independently from other dialect which make them different from others.

Consonants 
Most dialects in English use the shown 24 consonants.  is a little less common. There are, of course, exceptions to all of these in accents such as Hiberno English, New York, South Asian, etc.

Consonant examples 
The table below shows common examples of words in English that start with these letters.

Vowels 
English has an unusually large number of vowels. In English, vowels in different dialects change a lot. These vowels can also be written differently throughout different dialects. For example, the vowel in  is  in Received Pronunciation but  in General American.

John C. Wells made a popular lexicon set that shows the pronunciation in Received Pronunciation(RP) and General American(GA). It is shown below.

The next  three tables show the vowel phonemes in Received Pronunciation, General American and General Australian.

Some of the short vowels may also be combined with  ( bay,  buy,  boy), with  ( ,  beau) or with  ( peer,  pair,  poor). The vowel inventory of English RP in MacCarthy's system therefore totals only seven phonemes. Analyses such as these could also posit six vowel phonemes, if the vowel of the final syllable in comma is considered to be an unstressed allophone of that of strut. These seven vowels might be symbolized , , , , ,  and . Six or seven vowels is a figure that would put English much closer to the average number of vowel phonemes in other languages.

A radically different approach to the English vowel system was proposed by Chomsky and Halle. Their Sound Pattern of English  proposed that English has lax and tense vowel phonemes which are operated on by a complex set of phonological rules to transform underlying phonological forms into surface phonetic representations. This generative analysis is not easily comparable with conventional analyses, but the total number of vowel phonemes proposed falls well short of the figure of 20 often claimed as the number of English vowel phonemes.

Other pages 
* General American
 Received Pronunciation

References

Citations

Sources

Further reading 

Campbell, F., Gick, B., Wilson, I., Vatikiotis-Bateson, E. (2010), “Spatial and Temporal Properties of Gestures in North American English /r/”. Child's Language and Speech, 53 (1): 49–69

Dalcher Villafaña, C., Knight, R.A., Jones, M.J., (2008), “Cue Switching in the Perception of Approximants: Evidence from Two English Dialects”. University of Pennsylvania Working Papers in Linguistics, 14 (2): 63–64
Espy-Wilson, C. (2004), “Articulatory Strategies, speech Acoustics and Variability”. From Sound to Sense June 11 – June 13 at MIT: 62–63

Hagiwara, R., Fosnot, S. M., & Alessi, D. M. (2002). “Acoustic phonetics in a clinical setting: A case study of /r/-distortion therapy with surgical intervention”. Clinical linguistics & phonetics, 16 (6): 425–441.

Hoff, Erika, (2009), Language Development. Scarborough, Ontario. Cengage Learning, 2005.
Howard, S. (2007), “The interplay between articulation and prosody in children with impaired speech: Observations from electropalatographic and perceptual analysis”. International Journal of Speech-Language Pathology, 9 (1): 20–35.

Locke, John L., (1983), Phonological Acquisition and Change. New York, United States. Academic Press, 1983. Print.

Sharf, D.J., Benson, P.J. (1982), “Identification of synthesized/r-w/continua for adult and child speakers”. Donald J. Acoustical Society of America, 71 (4):1008–1015.
Wise, Claude Merton (1957), Applied Phonetics, Englewood Cliffs, NJ:  Prentice-Hall.

Other websites 

 University of Glasgow Dynamic Dialects Accent Map

Phonology
Pronunciation