Targeted Syntactic Evaluation of Language Models on Georgian Case Alignment
Daniel Gallagher, Gerhard Heyer
TL;DR
This work targets the targeted syntactic evaluation of transformer-based language processing on Georgian split-ergativity, using a Grew-driven minimal-pair test suite derived from the UD Georgian treebank. It introduces a dataset of 370 tests across seven tasks to probe nominative, dative, and ergative marking and evaluates seven language processing systems with word-level and sentence-level metrics. Results show robust nominative performance but systematic struggles with ergative marking, with accuracy correlating with case frequency in Georgian ($Nom > Dat > Erg$) and with data scarcity. The data-driven approach and public dataset provide a transferable framework for evaluating rare syntactic phenomena in low-resource languages and can guide future cross-language studies.
Abstract
This paper evaluates the performance of transformer-based language models on split-ergative case alignment in Georgian, a particularly rare system for assigning grammatical cases to mark argument roles. We focus on subject and object marking determined through various permutations of nominative, ergative, and dative noun forms. A treebank-based approach for the generation of minimal pairs using the Grew query language is implemented. We create a dataset of 370 syntactic tests made up of seven tasks containing 50-70 samples each, where three noun forms are tested in any given sample. Five encoder- and two decoder-only models are evaluated with word- and/or sentence-level accuracy metrics. Regardless of the specific syntactic makeup, models performed worst in assigning the ergative case correctly and strongest in assigning the nominative case correctly. Performance correlated with the overall frequency distribution of the three forms (NOM > DAT > ERG). Though data scarcity is a known issue for low-resource languages, we show that the highly specific role of the ergative along with a lack of available training data likely contributes to poor performance on this case. The dataset is made publicly available and the methodology provides an interesting avenue for future syntactic evaluations of languages where benchmarks are limited.
