The conjunction between coordination and subordination in missionary grammars of Aymara and Quechua

The history of linguistics provides insight into how a grammatical category is constructed within a linguistic theory, revealing the difficulties that arise when attempting to identify a universally valid definition. These difficulties still emerge today, particularly when linguists are challenged by a great crosslinguistic variation. An emblematic case is that of the conjunction, a grammatical category or part of speech often neglected in the history of linguistics (Berry-Rogghe 1970: 5), precisely because the boundaries of this category are difficult to draw in a clear and comprehensive way. Despite the fact that it has indeed been classified as one of the indeclinable parts of speech since antiquity, first by Greek and later by Latin grammarians (cf. Lenker 2010; Swiggers & Wouters 2015; de Jonge 2008; Gutiérrez Galindo 1989; Suto 2012), the definition of conjunction still shows the lack of a unanimous agreement among linguists (cf. among others Berry-Rogghe 1970; Haspelmath 2004; cf. among others also Prandi 2007; Laury 2008; Salvi 2014; De Cesare 2019; 2022). In fact, conjunctions behave as a multifunctional category that encodes different relations (from coordination to causality, conditionality, etc.) at different syntactic levels (single words, phrases, clauses, sentences). The cause of the lack of such agreement is ultimately to be found in the mismatch between the morphosyntactic and functional properties inherent to this category, which should be placed in a grammatical continuum between coordination and subordination (cf. Cristofaro 2003; Mauri 2008) and is therefore of crucial importance in our understanding of how the syntactic system of a given language works. Thus, despite the fact that coordination is a basic and universal syntactic construction (Mithun 1988: 331; 2003: 567), the world’s languages show a great variety in the way they grammaticalize coordination strategies. The consequence is the lack of a one-to-one correspondence between functions and forms, making it almost impossible to define a set of universally valid morphosyntactic and functional criteria. This issue has been constant throughout the history of linguistics, starting with the reflections of ancient grammarians (cf. Schad 2007: 85–86). For example, in the category of σύνδεσμοι Aristotle includes conjunctions (both coordinating and subordinating), adverbials, and also prepositions (Orlandini & Poccetti 2014: 268). More recently, some linguists (Prandi 2007; Salvi 2014; De Cesare 2019, 2022) have even argued in favour of eliminating this invariable part of speech, proposing to redistribute it in the class of adverbs (e.g. also), prepositions (e.g. after, because), and logical or syntactic operators (e.g. and, or, but, if, that).