The genitive prefix expresses possession. An example can be seen in the word ẹdẹda ẹẹ̀pẹrẹ “father’s portion”. The first word (ẹdẹda) names the possessor, but it is a noun functioning as an adjective (known as the classifier in functional terms). The possession is indicated in the second word (ẹẹ̀pẹrẹ), usually beginning a with a double vowel letter. The first of these vowels (ẹ) is a clitic prefix, expressing the act of possessing (such as the English possessive clitic “s”). It is pronounced with a neutral tone (unmarked Tone 3), while the second vowel (ẹ̀) is the part of the stem noun morpheme (ẹpẹrẹ) naming the possession. Notice that the falling tone marking is left out in the word because it is only relevant when the possessive clitic is also present. The second vowel is pronounced with a falling tone (Tone 2). Two more examples are ẹ̀wànrò uùbu, a “prisoner’s room” (prison) and mọ̀-ọ́dá oòfílọ́cẹn “my junior brother/sister’s shoe”. Finally, the possessive clitic is attached to the possession rather than the possessor as in some other languages such as English[1].
- Pronominal prefix
A Pronominal prefix is one that is used for different functions in a Ò̩kọ sentence. It makes delicate distinctions in personal pronouns. It can be used to mark the Subject or Object, Number, Persons, Possession etc, in a sentence. Examples of personal pronoun prefixes are in table 2 below.
| Person | Number | Root Clitic | Subject Prefix | Possessive | |
| 1st | SG | m- | non-progressive | progressive | m- |
| i– / ẹ- | mV- | ||||
| PL | t- | t +V | t- | ||
| 2nd | SG | w- | u– / w + V | wV- | w- |
| PL | n- | n + V | n- | ||
| 3rd | SG | y- | e– / a– | a– | y- |
| PL | b- | b/ – | b- | ||
| verbal group | nominal group |
Table 2: pronominal prefixes
The root clitics are the basic prefixed morphemes. Usually a simple sentence is made by adding a verb (V) to the root clitic to the prefix. Here are a few examples: ẹ- (1SG) + bori (swim) becomes ẹ̀–borí “I swam” just as a- (3SG) na (take) mọ (me) becomes à-na mọ́ “s/he took it (away) from me” or tì (1PL) wéyọ̀ “go out” becomes tì-wéyọ̀.
iii. Number Marking
Besides distinguishing number in pronominal context, there are also prefixes that indicate number in nouns. In the pluralization of nouns, the contrast between singular and plural is reflected in the choice between /o/ representing the singular morpheme and /e/ representing the plural morpheme at the initial position of the word. Number contrast is restricted to human, determiners and personified descriptive vocabulary.
| óró | “person” SING | = | éró “persons” |
| ógbén | “child”SING | = | égbén “children” |
| osuda | “elder”SING | = | isuda “elders” |
| ọcẹn | “leg”SING | = | ẹcẹn “legs” |
| óvia | “maiden”SING | = | ívia “maidens” |
| úbá | “hand” SING | = | ẹ́bá “hands” |
Beside this domain, which deals with the human being, human part or human relationship, and determiners, there is no inflection of nouns for number.