Natural and grammatical zero. The case of indeclinables

The focus of the present paper is on the opposition between linguistic phenomena labelled as vacanika ‘stated [be it by a rule or, which amounts to the same, through a specific linguistic sub- unit]’ and those considered as svabhavika (‘natural’), i.e., indepen- dent with respect both to specific rules formulated to account for them and to specific linguistic units expressing them. We owe such an opposition to Patan ̃jali who develops (and twists) hints alrea- dy present in Katyayana’s concept of an ‘independent’ linguistic phenomenon. The same opposition is also discussed in Bhartrhari’s long commentary in his Dıpika ad A 1.1.38 taddhitas ́ casarvavibhaktih. , which gives the name avyaya (‘indeclinable’) to secondary- affixes-ending forms without / not caused by all case endings. In this paper I highlight the evolution in the concept of zero in the earliest grammarians, which switches from being mainly meant, in Katyayana, to meet the requirements of semantic compositionality to becoming, in Bhartr.hari, a device to identify the specifically lin- guistic limits of zero-derivation.