The pair of letters making up a phoneme are not always adjacent. This is the case with English silent e. For example, the sequence a_e has the sound in English cake. This is the result of three historical sound changes: cake was originally , the open syllable came to be pronounced with a long vowel, and later the final schwa dropped off, leaving . Later still, the vowel became . There are six such digraphs in English, .Brooks (2015) Dictionary of the British English Spelling System, p. 460 ff
