Benchmark Almanac

Multilingual LibriSpeech

Models transcribe read audiobook speech in eight languages from LibriVox. Scored by word error rate.

Published at Interspeech 2020. Launch posts often report a subset of languages.

In the authors’ words

This paper introduces Multilingual LibriSpeech (MLS) dataset, a large multilingual corpus suitable for speech research. The dataset is derived from read audiobooks from LibriVox and consists of 8 languages, including about 44.5K hours of English and a total of about 6K hours for other languages. Additionally, we provide Language Models (LM) and baseline Automatic Speech Recognition (ASR) models and for all the languages in our dataset. We believe such a large transcribed dataset will open new avenues in ASR and Text-To-Speech (TTS) research. The dataset will be made freely available for anyone at http://www.openslr.org.

Abstract of MLS: A Large-Scale Multilingual Dataset for Speech Research (arXiv:2012.03411, CC0)
Made by Meta AI (Pratap et al.) Released Dec 2020 Speech recognition and translation All tasks public Last in a launch post Dec 2025 , dropped before it saturated Last model added Dec 2025
Level
Everyday Most adults, without training
Scored
Checked automatically A program checks the result against an answer key, unit tests or the expected final state.
Answers
Open-ended Free-form text, documents, designs or media judged as a whole.
1
Model scored in lab cards
1
Launch post lists it, from 1 lab
2
System cards report it, from 2 labs

Nova 2 Omni Preview leads with 4.70

Best score per model as labs report them in their own cards. Labs pick their own settings, so these compare less cleanly than independent runs.

  1. 1 Nova 2 Omni Preview 4.70
#ModelScoreSettingDateSource
1 Nova 2 Omni Preview 4.70 Dec 2025 Model card

Scores over time

All the scores we have, one dot each, so a model tested at several settings appears more than once.

Reported by the lab in its model card
4.70 2026 4.70 2026

Labs headline it less often now, last in Dec 2025

Launch posts from every lab that has listed it, one tick per post. Tall colored ticks include it, and short gray ones leave it out.

Amazon
DateLaunch postScoreAs the post writes it
2 Dec 2025 Nova 2 Omni Preview 4.7 MLS WER (English, Spanish, French, German, Italian)

2 system cards report it, from 2 labs

Besides launch posts, we read the system cards, model cards and technical reports labs publish with a release. They report far more, including safety and frontier-risk tests.

DateDocumentScoreAs the document writes itSection
2 Dec 2025 Nova 2 Omni Preview technical report 4.7 MLS WER, English, Spanish, French, German and Italian, lower is better (Table 7) Capabilities
17 Jul 2025 Voxtral Small technical report MLS WER per language, lower is better: nl 9.43, fr 3.73, de 5.57, it 8.44, pt 5.85, es 3.62 (Table 6) Capabilities

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