The middle voice is a notoriously controversial typological notion. Building on previous work (e.g. Kemmer, Suzanne. 1993. The middle voice. Amsterdam & Philadelphia: John Benjamins), in this paper I propose a new working definition of middle markers as inherently polyfunctional constructions which are partly associated with valency change in opposition to bivalent (or more) verbs and partly lexically obligatory with monovalent verbs. Based on this definition, the paper undertakes a systematic survey of 149 middle voice constructions in a sample of 129 middle-marking languages. Evidence from the sample shows that middle voice systems display a much richer variation in forms and functions than is reported in the literature. This richer empirical evidence challenges some of the mainstream views on middle marking, especially its purported connection with reflexivity and grooming-type events, and calls for an overall rethinking of the typology of the middle voice.

This paper discusses reciprocal constructions in Hittite, framed within the typology of reciprocals laid out by Nedjalkov (2007), König & Gast (2008), and Evans et al. (2011). Hittite attests to at least three reciprocal markers, that is, the middle voice, the particle =za, and three different polyptotic constructions, based on the iteration of the numeral šia- ‘one’, the demonstrative ka- ‘this’, and the noun ara- ‘fellow, comrade’ respectively. Synchronically, these three strategies cover different sub-domains of reciprocity, as they encode different kinds of reciprocal situations and display different syntactic properties. These differences can be accounted for by taking into account the processes out of which these constructions developed, which can be described in terms of grammaticalization (Heine & Miyashita 2008). In this respect, beside enriching our knowledge of reciprocals in Indo-European languages, this paper also contributes to our general understanding of the diachronic typology of reciprocal constructions.

The IE languages developed different strategies for the encoding of the passive function. In some language branches, the middle voice extended to the passive function to varying extents. In addition, dedicated derivational formations arose in a number of languages, such as the Greek -ē-/-thē- aorist and the Indo-Aryan -ya-presents. Periphrastic formations involving a verbal adjective or a participle are also widely attested, and played an important role in the building of the passive paradigm in e.g. Romance and Germanic languages. As the periphrastic passive is also attested in Hittite alongside passive use of the middle, both strategies seem to be equally ancient. Some minor strategies include lexical passives and the extensive lability of verbs. A survey of possible strategies provides evidence for the rise of a disparate number of morphemes and constructions, and for their ongoing incorporation into the inflectional paradigms (paradigmaticization) of given languages, thus adding to our knowledge about cross-linguistic sources of passive morphology and grammaticalization processes involved.