A formal noun is a grammaticalized noun which fulfills the function of a formative. Two main grammatical functions are documented:
- The formal noun functions as a pronoun.
- The formal noun functions as the head of a subordinate clause.
Ad 1: Engl. thing is a component of a pronoun in something, anything, everything etc. Jap. mono ‘thing’ fulfills these functions by itself. Yucatec Maya máak ‘person’ and ba'l ‘thing’ are provided with a focalizing suffix -x to yield the interrogative pronouns máax ‘who’ and ba'x ‘what’.
Ad 2: If the subordinate clause headed by the formal noun is oriented, the resulting relative construction is equivalent to a free relative clause or even an adverbial clause in other languages. If it is not, the resulting complex nominal may be a content clause. In , the formal noun toki is the head of the prenominal relative clause. In , the formal noun koto nominalizes the clause preceding it.
| . | terebi | =o | mi-ru | toki | =wa | heya | =o | akaru-kusi-te | ne |
| Jap | [TV | =ACC | look-PRS] | time | =TOP | room | =ACC | become.bright-CAUS-GER | VAL |
| When watching TV, make the room bright, alright? | |||||||||
| . | sora | =o | tob-u | koto | ga | deki-ru |
| Jap | [sky | =ACC | fly-PRS] | thing | NOM | be.able-PRS |
| (Someone) can fly the sky. | ||||||
The term ‘formal noun’ originates in Japanese linguistics and is there restricted to function #2. It extends easily to the description of other grammatical functions and other (though by no means all) languages.