f, g, s, x — 4 letters, 8 sounds
One of the complications of written English is that some sounds can be represented by more than one letter.
Each of the letters f, g, s, and x represents a distinct speech sound. These four letters can also be used as alternate spellings for sounds that already have distinctive letters of their own.
Ff /f/ as in fan
Gg /g/ as in get
Ss /s/ as in sip
Xx /ks/ as in six
They can also represent the sounds /v/, /g/, /s/, and /ks/:
Ff can also represent /v/ as in of
Gg can also represent the “soft” g sound /j/ as in Gene
Ss can also represent the sound /z/ as in his
Xx can also represent the sound /z/ as in xylophone
