Automatic speech recognition (ASR) remains challenging for low-resource languages, where the scarcity of transcribed speech limits the development of accurate systems. This challenge is particularly acute for African languages such as Ewe, which has millions of speakers but remains underrepresented in publicly available ASR resources and benchmarks. In this work, we consolidate, normalize, and partition existing Ewe speech resources into a standardized 174-hour Ewe ASR benchmark, the largest to date to our knowledge. We fine-tune and evaluate pretrained speech models, including Whisper and AfriHuBERT, to establish strong baselines on our benchmark. Whisper-medium achieves a word error rate (WER) of 37.98%, while AfriHuBERT achieves 39.70% on the test set. We further provide a qualitative analysis of common recognition errors. We release the benchmark under the name Nufo, derived from the Ewe word for "talk", accompanied by models and evaluation resources, to facilitate future research on Ewe and other underrepresented African languages.
Figures & tables
Source
Train
Valid.
Test
WAXAL
16,078
1,614
1,443
WAXAL + BibleTTS
36,011
1,614
1,443
WAXAL + BibleTTS + MINA
52,417
1,614
1,443
Table 1: Training, validation, and test set sizes, measured in number of utterances. Validation and test sets are fixed across all configurations to compare performance with the addition of more training data. Data comes from WAXAL [ 3 ] , BibleTTS [ 7 ] , and Common Voice - Mina (MINA) [ 2 ] .
Whisper
AfriHuBERT
medium
base
Parameters
769 M
74 M
97.4 M ⋆
Effective epochs
6.41
10.07
27
Batch / accum.
4 / 4
4 / 4
2 / –
Lang. condition
yo
yo
–
Objective
Seq2Seq
Seq2Seq
CTC
Table 2: Models and fine-tuning settings.
Data
Model
WER
CER
full
np
np_nd
full
np_nd
W
Whisper-base
46.84
42.10
39.36
16.23
14.18
Whisper-med
39.69
35.49
32.65
13.03
11.20
W+B
Whisper-base
44.92
40.48
37.73
15.29
13.22
Whisper-med
38.71
34.32
31.35
12.48
10.50
W+B+M
Whisper-base
44.72
40.28
37.57
15.07
13.08
Table 3: ASR results on the fixed 1,443-utterance test set (%). W = WAXAL, B = BibleTTS, M = Common Voice - Mina. Columns np , np_nd , represent performance when punctuation is removed and when punctuation and diacritics are removed, respectively.
Reference
Hypothesis
Error type / analysis
Whisper-medium
…utsu deka le mega foni e asi …
…utsu deka lé megafoni e asi …
Word boundary: mega foni → megafoni .
ame geewo tsi atsitre e goto.
ame geewo tsatsitre e goto.
Word boundary: tsi atsitre → tsatsitre .
…i kuku fitaa eye …
…kuku fita eye …
Ortho: fitaa → fita ; epenthetic vowel deletion.
…a Gego violet kple a Gego i …
…a Gego baulet kple a Gego i …
Lexical substitution: violet → baulet .
AfriHuBERT-CTC
Table 4: Representative errors on the Ewe test set. Ortho denotes orthography errors.
Recent large language models (LLMs) show strong speech recognition and translation capabilities for high-resource languages. However, African languages remain dramatically underrepresented in benchmarks, limiting their practical use in low-resource settings. While early benchmarks tested African languages and accents, they lacked exhaustive real-world noise and granular domain evaluations. We present AfriVox-v2, a comprehensive benchmark designed to test speech models under realistic African deployment conditions. AfriVox-v2 introduces "in the wild" unscripted audio for all supported languages. We also introduce strict domain verticalization, evaluating model accuracy across ten sectors including government, finance, health, and agriculture and conducting targeted tests on numbers and named entities. Finally, we benchmark a new generation of speech models, including Sahara-v2, Gemini 3 Flash, and the Omnilingual CTC models. Our results expose the true generalization gap of modern speech models in specialized, noisy African contexts and provide a reliable blueprint for developers building localized voice AI.
Large language models (LLMs) have driven substantial advances in speech language models (SpeechLMs), yielding strong performance in automatic speech recognition (ASR) under high-resource conditions. However, existing benchmarks predominantly focus on high-resource languages, leaving the ASR behavior of SpeechLMs in low-resource languages insufficiently understood. This gap is critical, as practical ASR systems must reliably support low-resource languages and generalize across diverse language families, and it directly hinders the deployment of SpeechLM-based ASR in real-world multilingual scenarios. As a result, it is essential to evaluate SpeechLMs on low-resource languages to ensure their generalizability across different language families. To address this problem, we propose LoASR-Bench, a comprehensive benchmark designed to evaluate low-resource automatic speech recognition (ASR) of the latest SpeechLMs across diverse language families. LoASR-Bench comprises 25 languages from 9 language families, featuring both Latin and non-Latin scripts, enabling cross-linguistic and cross-script assessment of ASR performance of current SpeechLMs. Experimental results highlight the limitations of the latest SpeechLMs in handling real-world low-resource languages.
Jianan Chen, Xiaoxue Gao, Tatsuya Kawahara +1
Kyoto University, Kyoto, Japan · Institute for Infocomm Research, Agency for Science, Technology and Research, Singapore
We evaluate whether compact domain-specialized ASR models can outperform massively multilingual foundation models for conversational African speech across 19 languages in the WAXAL corpus. Fine-tuned edge models achieve a macro-averaged WER of 38.0% compared to 64.9% for the best zero-shot baseline, a 26.9 percentage-point reduction using models 3−40× smaller. Results confirm that domain specialization dominates scale for spontaneous African speech. Cross-domain evaluation shows that fine-tuned models recover usable performance on out-of-distribution (OOD) speech, while zero-shot models regain an advantage when the test domain matches their pretraining distribution. A distributed native-speaker audit across all surveyed languages produces a linguistically-grounded error taxonomy, showing that CTC and autoregressive architectures behave differently across language families. We further show that WER alone misrepresents performance for syllabary-script languages where CER/WER ratios reveal substantially higher character-level accuracy than headline WER suggests. Finally, to contribute to future African ASR research, we release all model weights, fine-tuning and evaluation scripts, and a cleaned WAXAL subset covering all 19 languages.
Victor Tolulope Olufemi, Oreoluwa Babatunde, Ramsey Njema +28