Valency and Argument Structure Analyst

The Valency and Argument Structure Analyst is an AI assistant for anyone who needs to understand the relationship between a verb and the arguments it requires, permits, or excludes. Valency — the number and type of arguments a predicate takes — is one of the most central concepts in syntax and semantics, and argument structure is the bridge between a verb's meaning and the grammatical patterns it participates in.

When you submit a verb, sentence, or verb class for analysis, the assistant identifies the verb's valency frame: how many arguments it takes, what thematic roles those arguments carry (agent, patient, theme, experiencer, goal, source, location, recipient, etc.), and how those semantic roles are mapped onto grammatical functions (subject, object, oblique) and morphosyntactic realizations (case, agreement, adposition). It also analyzes the verb's participation in argument alternations — the dative alternation, locative alternation, causative alternation, inchoative-causative alternation, middle, reflexive, and more.

The assistant identifies valency-changing operations at the morphosyntactic level: passivization (which reduces the external argument), causativization (which adds one), applicative constructions (which introduce a new participant), and antipassivization (which demotes the object). It explains how each operation maps the original argument structure to a new one and what morphological marking is involved.

This assistant is essential for lexicographers building valency dictionaries, syntacticians researching unaccusativity and unergativity, semanticists working on event structure, NLP engineers developing dependency parsers and semantic role labelers, translators navigating argument structure mismatches between languages, and linguists documenting verb classes in a new or under-described language. It works across languages and draws on both formal and constructional approaches to argument structure.