Plural number denotes quantities greater than one. This is often marked on the noun to differentiate it from singular. Examples:

Notice most languages mark plurality by affixation (mostly suffixes): Georgian (-i is a case marker), Khakas, Limburgish, Pali and Zulu all glue an affix to the starts or ends of words, and Hebrew uses a more complex transfix.

Dinka is different, in that it alters the root to show plural number via apophony. This is not dissimilar to Indo-European Ablaut or Umlaut, where the vowels in Germanic languages' verbs often change in conjugation.

However, some words in some languages do not exhibit any marking of plurality. English ‘sheep’ is a common example, where no plural distinction is made from singular, leaving only context to differentiate. Latin ‘volgus’ (also ‘vulgus’) has no plural, as it is an uncountable noun. A noun is considered uncountable when it cannot have multiples of itself. For example, air and water are considered uncountable by many languages, since they are generic substances that cannot be neatly divided or grouped.

If such a word as ‘volgus’ is considered as uncountable, it could perhaps undergo a different marking of number where it is subdivided to show smaller components of the whole. English ‘water’ can be subdivided into ‘drop of water’ and variations thereupon; Dutch ‘snoep’ means sweets/candy, and a diminutive is applied to give ‘snoepje’, meaning a single sweet. Words like ‘snoepje’ can then be pluralised like most other nouns to give ‘snoepjes’, meaning sweets as countable units rather than a general foodstuff.

Dual number denotes pairs or groupings of two – plural marking here denotes grouplings of more than two. Arabic uses dual number to refer to body parts coming in pairs, such as eyes, nostrils or ears. Languages that lose dual number tend to lose this distinction first in nouns, then verbs, as in Old English and other older Germanic languages; however, a parent language that has dual number tends not to retain it for a specific class of morphology in descendants (this is unusual) and such branches often replace dual with plural entirely. Examples of nouns: