Hence, a linguistic index is any sign whose primary function is to signal another sign. Demonstratives, pronouns, proper nouns, grammatical morphemes, etc. are typical indices in language. According to the hypothesis put forward in this study, the morphological scale of indexicality should comprise four degrees and some subdegrees. Indeed, no derivational morpheme can convey an actual meaning unless it is connected with a given lexeme. Less natural indices are inflectional morphemes, as their content is relatively looser in relation to that of the lexical base.
Functional words constitute the third degree of the scale.
Their indexical force is less than that of inflectional affixes. The least natural index, that is to say the fourth degree of the scale, is represented by syntagmatic context, i.e. both sources and targets of morphological rules of conversion that principally refer to their syntagmatic collocation as far as to the disambiguation of their word-class.