Tigrinya Number Verbalization: Rules, Algorithm, and Implementation

TL;DR

This paper formalizes Tigrinya number verbalization rules, develops an algorithm, and releases an implementation, highlighting gaps in language model capabilities for this low-resource language.

Contribution

It provides the first systematic formalization and open-source algorithm for Tigrinya number verbalization, addressing a key resource gap.

Findings

Large language models struggle with Tigrinya number verbalization

Formal rules improve understanding of Tigrinya number expression

Open-source implementation supports future NLP applications

Abstract

We present a systematic formalization of Tigrinya cardinal and ordinal number verbalization, addressing a gap in computational resources for the language. This work documents the canonical rules governing the expression of numerical values in spoken Tigrinya, including the conjunction system, scale words, and special cases for dates, times, and currency. We provide a formal algorithm for number-to-word conversion and release an open-source implementation. Evaluation of frontier large language models (LLMs) reveals significant gaps in their ability to accurately verbalize Tigrinya numbers, underscoring the need for explicit rule documentation. This work serves language modeling, speech synthesis, and accessibility applications targeting Tigrinya-speaking communities.