A notoriously tough aspect for new cuers is assigning the correct handshape for /s/ and /z/. This decision occurs frequently in English because it affects plurals (e.g., cats, dogs, horses), posessives (e.g., Matt's, Pam's, and Rich's), as well as inflections for subject-verb agreement (hits, spills, washes).
1) If the root word ends in a voiceless sound (e.g., rat), the -s ending is pronounced (cued) /t/. Exceptions to this will be noted below for voiceless sounds that need a vowel before adding the plural marker.
| Final Phoneme of Root Word | Examples |
| /ppppppppp/ | chips, sleeps, cramps, drops, thanks |
| /kkkkkkkkk/ | bakes, works, drinks, bunks, books |
| /ttttttttt/ | its, rights, fists, gnats, hints |
| /fffffffff/ | laughs, paragraphs, goofs, whiffs, giraffes |
| /θththθththθthth/ | strengths, myths, froths |
2) If the root word ends in a voiced sound (e.g., phone), the -s ending is pronounced (cued) /z/. This inclueds root words that end with vowels as all vowels are voiced. Exceptions to this will be noted below for voiced sounds that need a vowel before adding the plural marker.
| Final Phoneme of Root Word | Examples |
| /ddddddddd/ | yards, worlds, leads |
| /ðt͟htHðt͟htHðt͟htH// | paths, soothes |
| /vvvvvvvvv/ | serves, saves, loves, drives, thieves |
| /rrrrrrrrr/ | scars, stairs, fears, cigars |
| /bbbbbbbbb/ | herbs, knobs |
| /nnnnnnnnn/ | clowns, mines, brains, lines, strains, acorns |
| /mmmmmmmmm/ | mom's, terms, crumbs, plums, items |
| /lllllllll/ | balls, sells, files, wheels, patrols, towels |
| /ggggggggg/ | wigs, legs, mugs, eggs |
| /ŋngngŋngngŋngng/ | meetings, fillings |
| [vowels] | pies, sees, chews, plays, knows, cowboys, canoes, annoys |
3) Exceptions to the rule above are words that end in a type of sound called sibilants. While one does not necessarily need to know the terminology, examples of each follows: /ʃshshʃshshʃshsh/ (wish), /ʧchchʧchchʧchch/ (church), /sssssssss/ (bus), /zzzzzzzzz/ (buzz), /ʒzhzhʒzhzhʒzhzh/ (garage), /ʤjjʤjjʤjj/ (judge). These words take the vowel /ɪĭiɪĭiɪĭi/ or /əəəəəəəəə/ before the vowel, but do not take /ɛěehɛěehɛěeh/.