SeamlessExpressive

Available as an interactive demo at seamless.metademolab.com, SeamlessExpressive aims to preserve the full emotional and stylistic character of a speaker's voice when translating into another languagecapturing not just meaning but mood, cadence, and personality.

Traditional machine translation systems discard prosodic information when converting speech from one language to another, producing flat, robotic output that loses the human warmth of the original speaker. SeamlessExpressive was engineered specifically to address this gap.

The model preserves speech rate, pauses, vocal tone, and expressive style alongside the semantic content, resulting in translated audio that sounds like the same person speaking a different language rather than a generic synthesized voice.

The model builds on SeamlessM4T, Meta's massively multilingual multimodal translation foundation. SeamlessExpressive handles input from nearly 100 languages and can produce expressive output in four languages: English, Spanish, German, and French.

This makes it immediately accessible for a wide range of cross-linguistic communication scenarios, from international content creators who want to reach audiences in multiple markets to researchers studying cross-cultural communication.

SeamlessExpressive is part of Meta's broader Seamless suite, which also includes SeamlessStreaminga model that performs simultaneous real-time translation for approximately 100 languages.

The two capabilities are combined in a unified model simply called Seamless, which offers both streaming translation for live conversations and expressive translation for recorded or studio-quality speech. The demo interface allows users to record their own voice and hear an expressive translation in seconds.