Many sources have published the rules for pronouncing s or z at the end of a 3rd person singular or plural word. Fewer sources have published other rules governing S and Z. This is what I've come up with:
4) Z can be
silent: rendezvous, laissez-faire
1)
The following letter combinations often make the “S”
sound: ce, ci, cy, x, psy, consonant +se, cc +e, i or y, sc, ss and s
a.
Ce: Ice, rice, price, entrance, since, face, trace, peace,
place, niece, procedure, necessary, police, office, license, cent, certain,
receive, cell
b.
Ci: Accident, decision, circulate, acid, aerobicize,
anglicize, annunciate, carcinogen, cigar, anticipate, homicide, society,
athleticism, calcium, cinch, circus, civil, crucify, decimal, docile
i.
Exceptions: (sh instead) ancient, commercial, artificial,
social, appreciate, atrocious, suspicious
c.
Cy: Lucy, lacy, fancy, juicy, cylinder, cycle, vacancy,
conspiracy, cymbal, cyanide, cyber, cypress, cyst
d.
X + consonant, unstressed vowel or final X: excavate, exceed,
exhale, axle, expire, expert, expect, extreme, extra, next, elixir, toxic,
axon, fix
i.
Exception: (sh instead) sexual, luxury, complexion
e.
Ps (beginning of word): Psychology, pseudo, psalm, psyllium
f.
Consonant +se: Course, worse, disperse, hoarse, corpse,
eclipse, tense, expense, censor, rinse, immense, defense, Farsi, absent, false,
curtsey
i.
Exception: observe, birdseye, cleanse
g.
Cc + e, i or y: accent, accept, accident, success, eccentric,
accessory, vaccine
i.
Exception: bocci, soccer, cappuccino
h.
Sc: ascent, crescent, descend, disciple, fascinate,
fluorescent, isosceles, luminescent, miscellaneous, muscle, obscene,
resuscitate, scenario, scene, scent, science, scissors
i.
Ss: lesson, gloss, chess, bassoon, assign, assist,
assassinate, address
j.
s: soft, escape, small, statistics, mistake, chemistry,
minister, register, miniscule, slow, snow, spout, spray, display, squeak, sweet
2)
The following letter combinations often make the “Z” sound:
a.
X + stressed vowel: examine, example, exact, exist, executive,
exotic, exude, exuberant, exult
i.
Exception: ation words: taxation. relaxation
b.
S is between two vowel sounds: music, reason, season, cousin,
disease, easy, posie, resign, isn’t, present, physician, position, positive,
president, preside, visit, physique
i.
Exception: second
vowel sound begins plural or 3rd person ending or other suffix: leases, places, nooses, houses (noun),
defenses, busing, curiosity
ii.
Exception: (zh instead) ambrosia, corrosion
iii.
Exception: atherosclerosis
c.
Vowel + se: use (verb), these, lose, cause, because, choose,
phase, tease, raise, cruise
i.
exceptions: promise, house (noun), use (noun), close (adj.),
mouse, lease, loose, moose, noose, caboose, chartreuse, dose
d.
ZZ: dizzy, puzzle,
fuzz
i.
Exception: (Italian words) pizza, pizzicato
e.
Z: Zipper, crazy, doze, razor
f.
Other: Tuesday, Wednesday, Thursday, lens
3)
S can be silent:
aisle, island, isle, debris, Arkansas, Illinois, rendezvous, corps
