The nature of phonological, morpho-phonological and morphological alternations

This strand of my program explores the representational and the computational relationships among phonological, morpho-phonological, and morphological alternations. Morphological and phonological theories have primarily focused on two main questions about alternations.

1. What the representational status of alternations? Derivation vs. representation; computation vs. storage

The first question concerns the definition of the grammatical procedure under which a phonological or morphological representation undergoes a given set of changes, before surfacing as the corresponding phonetic representation. One path of research seeks to define the best procedural approach to account for purely phonological changes (in which both the target and the trigger are phonological in nature). Derivational theories have claimed that phonological alternations result from application of sequential rules applying at different derivational steps (e.g., Chomsky & Halle, 1968). Representational theories have claimed instead that alternations result from the selection of the optimal candidate via evaluation against a language-specific constraint ranking (e.g., Prince & Smolensky, 1993/2004). On this issue, Petrosino & Calabrese (2022) present an overview of all the accounts proposed for Romance palatalization, and ultimately show that a derivational framework can account for palatalization in a more articulatory-grounded and less stipulative way than a representational framework.

A second path of research seeks to identify an agreed-upon heuristic to best account for the different kinds of alternations sketched above. In general, all alternations involve two segments: the target (i.e., the segment undergoing the change) and the trigger (i.e., the segment causing the change). The nature of the two segments may be either phonological (i.e., involving phonological information) or morphological (i.e., involving morphological information); this taxonomy logically allows for four possible target-trigger combinations, which can all be identified in human languages. A type of alternation that has been at the center of a vivid debate involves a phonological target conditioned by a morphological, or a morpho-phonological trigger. An example of this type of alternation is the masculine forms of the Standard Italian definite determiner: it realizes as _il [il] _(singular) ~ i [i] (plural) before a noun beginning with a simple consonant (e.g., il [k]ane ‘the dog’ ~ i [k]ani ‘the dogs’), lo [lo] (singular) ~ gli [λi] (plural) before a noun beginning with a complex consonant (e.g., lo [st]ato ‘the state’ ~ gli [st]ati ‘the states’). I have argued that the forms of Italo-Romance determiners (Petrosino 2018) can be better accounted for in a derivational account, which, unlike any representational account, is able to catch language-wide generalizations via application of morpho-phonologically conditioned rules.

Currently, the processing of phonological and morphological alternations is relatively understudied in word processing. I am exploring the extent to which processing time may be a function of the number of the derivational steps the parser needs to go through to retrieve to the correct (morpho-)phonological representation. In essence, this approach applies the theory of derivational complexity (DTC: Miller & Chomsky, 1963) to the (morpho-)phonological component of the grammar, under the assumption that any potential impact on processing time may be measurable in terms of reaction times (RTs; Phillips, 1996). If that is the case, derivational theories seemingly predict that processing time increases along with the number of steps required for the parser to recognize the phonological representation, thus slowing down recognition and ultimately increasing RTs.

2. What are the grammatical conditions of alternations?

The second question regarding the nature of alternations concerns the definition of the grammatical conditions under which alternations may arise. This topic has been at center of the debate within the framework of Distributed Morphology, in which word formation is seen in purely syntactic terms, as a result of cyclic movement of functional morpho-syntactic heads (Halle & Marantz, 1993). The most-accepted hypothesis maintains that alternations may arise only when the target and the trigger heads are syntactically adjacent to one another (node adjacency hypothesis: Embick, 2010). The node adjacency hypothesis has been recently challenged and replaced with a less restrictive one, whereby alternations may be triggered by a span of different morpho-syntactic heads (span adjacency hypothesis: Merchant, 2015). On this issue, Christopoulos & Petrosino (2018) provide striking evidence in support of the node adjacency hypothesis, in showing that roots alternate when the trigger node is adjacent to the root (e.g., ser-n-i ‘drag-IMPFV.ACT-3SG’ ~ sir-θ-i ‘drag-PFV.NACT-3SG’, where the Aspect/Voice head -θ- triggers ablaut on the root), but they don’t when an additional head intervenes in between (e.g., pal-ev-i ‘fight-v-IMPFV.ACT-3SG’ ~ pal-ef-θ-i ‘fight-v-PFV.NACT-3SG’, where the verbalizer -az- intervenes between the triggering Aspect/Voice head -θ- and the root).

Under similar theoretical assumptions, Calabrese & Petrosino (2023) discuss the morpho-syntactic behavior of the so-called “thematic vowel” (TV), the root-adjacent vowel that typifies Indo-European verbal morphology, across Sanskrit, Ancient Greek, and Latin. We take issue with the common trend that, in the wake of the seminal work by Aronoff (1994) on Latin verbal morphology, considers TVs cross-linguistically “ornamental” (i.e., lacking any morpho-syntactico-semantic information) by default. We show that, unlike Latin (and therefore Romance), Sanskrit and Ancient Greek TV are fully functional, and argue for a diachronic account whereby the original functionality of such pieces was gradually lost over time, and finally gave rise to the modern Romance verbal ornamental system.