Pronountiation matters

"Yours not to reason why. Yours but to do and die". The reasons that two letters have the same sound and also that one letter may have several sounds are historical and because English has grown by assimilating words (with their spellings) from other languages and that, over time, words have changed their pronunciation but retained their spelling. This began even before English was invented. The Latin alphabet had no J and it borrowed the letter K from the Greeks. It also had only one letter 'V' for the voiced fricative /v/ and the vowel /u/ (and for the vocalic consonant /w/). Other languages had different sounds which Latin did not possess so the mediaeval monks (who were mostly responsible for our orthography) used existing Latin letters to represent different sounds. There were also different monks with different ideas about how sounds should be represented. The letter J (representing the /dzh/ sound) was quite a recent introduction. It used to be just another form of the letter 'I' and came to be used in Norman French for a /y/ sound which, in some dialects, was pronounced as /zh/. 'George' is spelt with a 'G' because it is a Greek word which began with the Greek 'gamma' (and was pronounced 'Georgios', with both 'g's as the 'g' in 'good'). John is spelled with a 'J' because it comes from the Greek 'Ioannis'. 'C' usually has the sound of 'k; before 'o', 'a' and 'u' but the sound of 's' before 'e' and 'i'. In Latin, it followed similar rules except that it was probably closer to 'g' when it was a glottal and pronounced /ts/ rather than /s/ in other cases. The names 'Gaius' and 'Caius' were interchangeable in Latin and the 'a' was probably silent (only being there to make the sound hard) so that the name was pronounced something like /kees/ or /geeus/.