Number can be marked on nouns[1] in a variety of ways.

Types:

NoNum: Grammatical number of nouns is not marked syntactically or morphologically.

NumW: Grammatical number of nouns is marked syntactically, with the use (or lack) of a separate word indicating number. These words show free word order or fixed word order separate from that of the noun or noun phrase. They may be synthetic (also known as polyexponential), expressing grammatical features in addition to number, such as agreement.

NumKlit: Grammatical number of nouns is marked using clitics. Clitics are morphemes that attach to the entire noun phrase or some element outside the noun phrase, rather than directly to the noun. They may be synthetic (also known as polyexponential), expressing grammatical features in addition to number, such as agreement.

NumRedupl: Grammatical number is marked by total reduplication of the noun.

NumPartRedupl: Grammatical number is marked by partial reduplication of the noun (first or last syllable).

NumTon: Grammatical number is marked by tone.

NumIntrofl: Grammatical number is marked morphologically by internal flexion.

NumPrefAn: Grammatical number is marked morphologically using analytical prefixes (monoexponential; i.e., the prefix expresses only the number).

NumPrefSynt: Grammatical number is marked morphologically using synthetic prefixes (polyexponential; i.e., the prefix expresses other grammatical features, such as case).[2]

NumSuffAn: Grammatical number is marked morphologically using analytic suffixes (monoexponential; i.e., the suffix expresses only the number).

NumSuffSynt: Grammatical number is marked morphologically using synthetic suffixes (polyexponential; i.e., the suffix expresses other grammatical features, such as case).[3]

When a language displays more than one type of marking, multiple values can be listed. If one type is dominant, a slash (/) can separate the values, with the dominant value appearing first; if no type is dominant, the values are listed with an ampersand (&) separating them.

[1] This parameter also applies to non-personal pronouns. The plural is taken as the prototypical number.

[2] If a language has a case system and the morphemes of the non-nominative cases are synthetic (polyexponential) in the plural, then nominative plurals without case marking are considered synthetic as well.

[3] If a language has a case system and the morphemes of the non-nominative cases are synthetic (polyexponential) in the plural, then nominative plurals without case marking are considered synthetic as well.