Lawrence Wolf-Sonkin
Research Areas
Authored Publications
Sort By
Preview abstract
The Private-Use Area (PUA) is an important part of the Unicode standard. It consists of several ranges of Unicode code points with no official character assignments. The PUA is primarily used as a temporary representation mechanism for characters outside the official standard to facilitate text entry and display of orthographies that cannot be adequately represented by other means. The primary downside of PUA is that characters lose their semantics if the pairing with the corresponding display font is broken. Consequently, they cannot be faithfully displayed in the general setting. Large-scale multilingual web corpora inevitably contain PUA code points of unclear provenance. We investigate the distribution of PUA characters within large-scale datasets, using filters for determining PUA tokens of linguistic interest. We analyze the resulting distributions both across scripts and writing systems, and show that PUA-bearing tokens can signal texts from under-represented languages. We explore whether an off-the-shelf large language model (LLM) can classify PUA characters as those that constitute relevant orthographic signals vs. punctuation or other noise. While the proportion of PUA-bearing paragraphs in the original corpora are small, we identify millions of paragraphs, and we argue that such data is still important for the long tail of data-scarce orthographies. Moreover, as a primary Unicode mechanism for poorly represented writing systems, the PUA is here to stay.
View details
Extensions to Brahmic script processing within the Nisaba library: new scripts, languages and utilities
Raiomond Doctor
Proceedings of the 13th Language Resources and Evaluation Conference.(LREC), European Language Resources Association (ELRA), 20-25 June, Marseille, France (2022), 6450‑6460
Preview abstract
The Brahmic family of scripts is used to record some of the most spoken languages in the world and is arguably the most diverse family of writing systems. In this work, we present several substantial extensions to Brahmic script functionality within the open-source Nisaba library of finite-state script normalization and processing utilities (Johny et. al. , 2021). First, we extend coverage from the original ten scripts to an additional ten scripts of South Asia and beyond, including some used to record endangered languages such as Dogri. Second, we augment the language layer so that scripts used by multiple languages in distinct ways can be processed correctly for more languages, such as the Bengali script when used for the low-resource language Santali. We document key changes to the finite-state engine required to support these new languages and scripts. Finally, we add new script processing utilities, including lightweight script-level reading normalization that (unlike existing visual normalization) does not preserve visual invariance, and a fixed-input transliteration mechanism specifically tailored to Brahmic text entry with ASCII characters.
View details
Finite-state script normalization and processing utilities: The Nisaba Brahmic library
The 16th Conference of the European Chapter of the Association for Computational Linguistics (EACL 2021): System Demonstrations, Association for Computational Linguistics, [Online], Kyiv, Ukraine, April, 2021, pp. 14-23
Preview abstract
This paper presents an open-source library for efficient low-level processing of ten major South Asian Brahmic scripts. The library provides a flexible and extensible framework for supporting crucial operations on Brahmic scripts, such as NFC, visual normalization, reversible transliteration, and validity checks, implemented in Python within a finite-state transducer formalism. We survey some common Brahmic script issues that may adversely affect the performance of downstream NLP tasks, and provide the rationale for finite-state design and system implementation details.
View details
Processing South Asian languages written in the Latin script: the Dakshina dataset
Christo Kirov
Sabrina J. Mielke
Keith Hall
Proceedings of the 12th Conference on Language Resources and Evaluation (LREC) (2020), 2413–2423
Preview abstract
This paper describes the Dakshina dataset, a new resource consisting of text in both the Latin and native scripts for 12 South Asian languages. The dataset includes, for each language: 1) native script Wikipedia text; 2) a romanization lexicon; and 3) full sentence parallel data in both a native script of the language and the basic Latin alphabet. We document the methods used for preparation and selection of the Wikipedia text in each language; collection of attested romanizations for sampled lexicons; and manual romanization of held-out sentences from the native script collections. We additionally provide baseline results on several tasks made possible by the dataset, including single word transliteration, full sentence transliteration, and language modeling of native script and romanized text.
View details
Latin script keyboards for South Asian languages with finite-state normalization
Vlad Schogol
Michael Riley
Proceedings of the 14th International Conference on Finite-State Methods and Natural Language Processing, Association for Computational Linguistics, Dresden, Germany (2019), pp. 108-117
Preview abstract
The use of the Latin script for text entry of South Asian languages is common, even though there is no standard orthography for these languages in the script. We explore several compact finite-state architectures that permit variable spellings of words during mobile text entry. We find that approaches making use of transliteration transducers provide large accuracy improvements over baselines, but that simpler approaches involving a compact representation of many attested alternatives yields much of the accuracy gain. This is particularly important when operating under constraints on model size (e.g., on inexpensive mobile devices with limited storage and memory for keyboard models), and on speed of inference, since people typing on mobile keyboards expect no perceptual delay in keyboard responsiveness.
View details
