1. After these unvoiced consonant sounds /p/,/f/ ,/t/, /k/, and /θ/, the final s is pronounced /s/.
For example: groups. products, stocks
2. After these voiced consonant sounds /b/, /d/, /g/, /v/, /ð/, /l/, /m/, /n/, and /ŋ/, the final s is pronounced /z/.
For Example: teams, rules. standards
3. After these other consonant sounds /s/, /v/, /ʃ/, /ʧ/,/ʒ/, and /ʤ/, the final s is pronounced /ɪz/.
For Example: expenses. percentages
Exercise: Look at these plural nouns and say them aloud. Tick the correct column.