REGULAR AND IRREGULAR PLURALS
Regular plurals are formed by the addition of a suffix: /iz/ after a sibilant, as in kiss – kisses, church – churches (with the spelling -es); /s/after a voiceless consonant as in books, cakes; or /z/after a voiced consonant, as in pole – poles, streams – streams, or a vowel eye – eyes, cry – cries (the spelling is -s, with y becoming i after a consonant, but not after a vowel: day – days). A number of words of classical origin retain their original plurals, for example: phenomenon – phenomena; criterion – criteria.
Most common irregular plurals are formed by a change of vowel (or of two vowels): woman – women, man – men, tooth – teeth. Child – children has developed a ‘double’ plural, having both a vowel change and a suffix. Another group marks the plural by a consonant change: half – halves; calf – calves; loaf – loaves. A third group of nouns have the same form for both singular and plural. This is known as ‘zero plural’: trout, salmon, sheep, deer, series, species, aircraft.
