Three Pronunciation Endings For Plural Nouns

/s/, /z/, and /ɪz/

/S/ sound
Used after voiceless sounds (quiet consonants).

If the word ends with:

• /p/
• /t/
• /k/
• /f/
• /θ/ (think)
  
  Then the plural ends with /s/.
  
  Examples:
cups → /kʌps/
cats → /kæts/
books → /bʊks/
cliffs → /klɪfs/
months → /mʌnθs/
  

/z/ sound

Used after voiced sounds (sounds your throat vibrates).

If the word ends with:

vowels (a, e, i, o, u sounds)
voiced consonants: b, d, g, v, ð, m, n, ŋ, l, r, vowels

Then the plural ends with /z/.

Examples:

dogs → /dɔːgz/
bags → /bægz/
cars → /kɑːrz/
beds → /bedz/
rooms → /ruːmz/

/ɪz/ sound
Used after hissing / buzzing sounds (sibilants).

If the word ends with:

• s / z
• sh
• ch
• x
• ge / j

Then the plural ends with /ɪz/.

Examples:

boxes → /bɒksɪz/
buses → /bʌsɪz/
roses → /rəʊzɪz/
dishes → /dɪʃɪz/
watches → /wɒtʃɪz/

Voiceless ending → /s/
Voiced ending → /z/
S / Z / SH / CH / X / J → /ɪz/