we all know that there are 26 letters of the alphabet but these letters represent 46 sounds in the standard English speech, i.e. Received Pronunciation (RP) of England. The symbols of RP Consonants are the same in Daniel Jones' English pronouncing Dictionary (14 edition) , A. S. Hornby' s The Advanced Learner's Dictionary of current English (4 edition) and A. C. Gimson's An introduction to the Pronunciation of English ( 4 revised edition ) but the symbols used for vowels and Diphthongs slightly different.