DIALECTBENCH: A NLP Benchmark for Dialects, Varieties, and Closely-Related Languages
Fahim Faisal, Orevaoghene Ahia, Aarohi Srivastava, Kabir Ahuja, David Chiang, Yulia Tsvetkov, Antonios Anastasopoulos
TL;DR
DialectBench introduces the first large-scale NLP benchmark focused on language varieties, aggregating 281 varieties across 40 language clusters and 10 tasks to reveal systematic disparities between standard and non-standard varieties. The work details a comprehensive framework for variety selection, cluster mapping, representative design, task inclusion, and evaluation principles, and provides baseline results using mBERT, XLM-R, NLLB, and Mistral-7B across zero-shot, fine-tuning, and in-context learning settings. It quantifies dialectal gaps with a relative metric across tasks and clusters, highlights the impact of script and data availability, and discusses implications for model robustness and data quality. Overall, the study establishes a foundation for rigorous dialectal NLP benchmarking and points to practical paths for expanding resources, refining metrics, and improving cross-linguistic robustness in real-world settings.
Abstract
Language technologies should be judged on their usefulness in real-world use cases. An often overlooked aspect in natural language processing (NLP) research and evaluation is language variation in the form of non-standard dialects or language varieties (hereafter, varieties). Most NLP benchmarks are limited to standard language varieties. To fill this gap, we propose DIALECTBENCH, the first-ever large-scale benchmark for NLP on varieties, which aggregates an extensive set of task-varied variety datasets (10 text-level tasks covering 281 varieties). This allows for a comprehensive evaluation of NLP system performance on different language varieties. We provide substantial evidence of performance disparities between standard and non-standard language varieties, and we also identify language clusters with large performance divergence across tasks. We believe DIALECTBENCH provides a comprehensive view of the current state of NLP for language varieties and one step towards advancing it further. Code/data: https://github.com/ffaisal93/DialectBench
