The best known marker is the silent E, which changes the sound of the vowel that precedes it. For example? mat - mate. sit – site. cut – cute.
Next is the following R, which usually changes the sound of the preceding vowel. Pronounce the following words: car, farm, charm, her, nerd, perk, shirt, birth, dirt, ford, cord, lord, curl, hurt, murmur, turf. The vowels in these words are special vowel sounds, neither short nor long, but somewhere in between. Similarly, the following L occasionally affects the preceding vowel, as in palm, half, calf.
Next is the CK, which tells us that the preceding vowel is short. Examples are tick, tack, deck, dock, and duck.
Those irritating double consonants are there to remind us that the preceding vowel is short. It’s hammer not hamer, slimming not sliming, better not beter, rotten not roten, and cutter not cuter.
Another pronunciation marker is TCH, which also warns us that the preceding vowel is short. Examples include catch, fetch, ditch, botch, and hutch.
Similarly, the DGE is another marker that warns us that the preceding vowel is short. Examples are edge, hedge, badge, ridge, dodge, and nudge.
The letter C is an especially important marker. When it precedes the soft vowels E, I and Y, the C will sound like S: cent, civil, cylinder. When it precedes the hard vowels A, O, and U, the C will sound like K: cat, cocoa, cucumber.
The G is very similar to the C. The vowel after the G allows us, for example, to distinguish between a giraffe and a gazelle. But it has exceptions, like get, finger, gear, girl, give, and begin, all of which are hard G’s followed by the soft vowels.
Another G issue is GU, which is to prevent the hard G from turning soft when it is followed by E or I. Is fugue pronounced FYOOG or FYOOJ? (The answer is FYOOG.) Other examples are guarantee, guest guess, guinea, guitar, beguile, and plague. The G in each of these words is a hard G. But note the word catalogue. This word is today often spelled catalog because the UE ending is not needed.
Yes, there are numerous unneeded letters in English spelling, but let us remember that some of those weird spellings are there to help us.