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Speech & Sound · 2023

SeamlessM4T & the Seamless family

A real-life Babel Fish that keeps your voice

open source 2.3B (SeamlessM4T v2 Large) params

Latest: SeamlessM4T v2 + SeamlessExpressive/Streaming (Nov 2023); Nature paper Jan 2025

One model for speech-to-speech, speech-to-text, text-to-speech, text-to-text translation and ASR across ~100 languages (Aug 2023). The v2 suite (Nov 2023) added SeamlessExpressive — preserving your tone, pauses, and emotion across languages — and SeamlessStreaming, translating with ~2-second latency before the speaker finishes. Published in Nature in January 2025.

Why it matters

Collapsed speech-to-speech, speech-to-text, text-to-speech and text translation into one model for roughly 100 languages, then added expressive translation that preserves tone and pauses and streaming translation at about two seconds of latency. Published in Nature in January 2025, it is the reference open system for speech translation.

Facts

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Lineage

Descends fromNo Language Left BehindMassively Multilingual Speech

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Sources

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