Spelling Irregular Plurals

Many English words simply require adding an ‘s’ when forming a plural. ‘Table’, for example, becomes ‘tables’. There are, however, a host of words that don’t stick to this rule. These are known as irregular plurals.

Luckily, there are some guidelines which can help you spell irregular plurals correctly. These aren’t strict rules, as there are always exceptions, but they can help while writing. As ever, though, if in doubt, check a dictionary.

Often, these guidelines relate to the ending of a word.

Words Ending ‘-us’

Words ending ‘-us’ (e.g. ‘alumnus’) often take the plural ending ‘-i’ (e.g. ‘alumni’). Other such words include:

Note that the word ‘virus’ does not follow this pattern and is spelled ‘viruses’ in the plural. In addition, in some cases the ‘i’ ending is considered old-fashioned. For example, although ‘hippopotami‘ is accepted as a plural of ‘hippopotamus’, ‘hippopotamuses‘ is more common in modern English.

Words Ending ‘-on’ or ‘-um’

Words ending ‘-on’ (e.g. ‘phenomenon’) often take the plural ending ‘-a’ (e.g. ‘phenomena’). Other words which follow this pattern include:

As above, though, sometimes using the ‘-a’ ending can seem old-fashioned. ‘Stadia‘, for instance, is accepted as a plural of ‘stadium’, but ‘stadiums‘ is much more common these days.

Words Ending ‘-f’ and ‘-fe’

Words ending ‘-f’ or ‘-fe’ (e.g. ‘leaf’ and ‘knife’) typically replace the ‘-f’ or ‘-fe’ with ‘-ves’ in the plural (e.g. ‘leaves’ and ‘knives’). Other such words include:

There are, however, multiple exceptions to this rule, including ‘beliefs’, ‘chiefs’, ‘reefs’ and ‘cuffs’.

Words Ending ‘-is’

Words ending in ‘-is’ (e.g. ‘analysis’) take the plural ending ‘-es’ (e.g. ‘analyses’). See also:

Words Which Stay the Same

There are also words which are spelled the same in the singular and the plural. Examples include ‘moose’, ‘deer’, ‘sheep’, ‘equipment’ and ‘furniture’. Thus, one can speak both of a single ‘sheep’ and a ‘flock of sheep’.

If you would like further guidance about spelling or academic writing, or to have a 500-word sample of your writing proofread for free, get in touch with the professionals at Proofed today!