suffixes and use of double letters
is one part of English spelling which is actually quite regular.
At least 226 common one-syllable words
(bag, bat, can, cap, cat, chat, clam, clan, clap, crab, dab, dam, drab, drag, fad, fan, fat, flap, flat, gag, glad, grab, ham, hat, scrap, scan, sap, sag, sad, rat, rap, ram, plan, pat, pan , pad, nag, mat, map, mad, lap, lag, jam, jab, slam, slap, snap, span, stab, strap, tag, tan, tap, trap, wag, wrap, yap, zap,
bed, beg, bet, fret, get, hem, jet, leg, let, net, peg, pen, red, set, stem, step, trek, vet, web, wet,
bid, big, bin, bit, brim, chip, clip, crib, dig, dim, dip, drip, fit, flip, flit, grim, grin, grip, grit, hip, hit, jig, kid, lid, lip, pig, pin, pip, quit, quiz, rib, rid, rig, rim, rip, shin, ship, sin, sit, skid, skim, skin, skip, slim, slip, slit, snip, spin, spit, split, strip, swim, thin, tin, tip, trim, trip, twig, twin, whiz, win, wit, zip,
blot, bob, bog, chop, cop, crop, dog, don, dot, drop, flog, flop, fog, grog, hog, hop, hot, job, jog, jot, knot, lob, log, lop, mob, mop, nod, plod, plot, pod, pot, prod, prop, rob, rot, shop, slog, snob, sob, spot, stop, throb, top, tot, trot,
but, club, cub, cup, cut, drug, drum, fun, glum, grub, gun, hug, hum, jug, jut, lug, mud, mug, nut, plug, plum, run, scrub, shrub, shrug, shun, shut, slug, slum, strum, strut, stud, stun, sum, sun, thud, thug, tug, up)
double their final consonant when made longer with suffixes which begin with a vowel, like -ed, -ing, -ish, -er, -y.
But even they are not completely problem-free with verbs. Adding -ed to the 200 or so verbs among the above and doubling their last letter is easy enough, if u know that the verb is regular.
Unfortunately 171 common verbs are irregular in the past tenses (e.g. 'go - went, have done; write - wrote, have writtten', rather than 'bag - bagged, have bagged).