‘Letters’ refers to the actual physical, or written, letters of the alphabet (also called ‘graphemes’). ‘Sounds’ are the sounds that these letters make (also called ‘phonemes’). There are 26 letters in the alphabet. There are about 44 sounds that make up all the words in the English Language.

The relationship between the letter (s) and the sound is called a letter-sound correspondence, also known as a grapheme-phoneme correspondence (or GPC).