X-Translator: A Real-Time Multilingual Speaker-Aware Speech-to-Speech Translation System
This work provides an open and reproducible real-time S2ST system for researchers and developers, addressing practical deployment challenges in multi-speaker conversations.
The X-Translator system addresses the challenge of real-time speech-to-speech translation (S2ST) in long-form and multi-speaker conversations by combining streaming ASR, machine translation, and prompt-conditioned TTS. It achieves this by using incremental segment commitment for unstable ASR streams and an online speaker prompt manager for speaker-specific voice prompts, leading to improved voice stability and speaker preservation in multi-speaker scenarios.
Real-time speech-to-speech translation (S2ST) systems must balance translation quality, latency, speech naturalness, and speaker consistency. Publicly documented S2ST systems have advanced direct, multilingual, streaming, and expressive modeling, while proprietary products and APIs increasingly expose real-time translation capabilities to users. However, practical deployment remains challenging for open and reproducible systems, especially in long-form and multi-speaker conversations where partial ASR hypotheses are unstable, turn boundaries are ambiguous, and target speech must be generated with an appropriate speaker prompt. We present X-Translator, a low-cost modular cascaded S2ST system that combines streaming ASR, machine translation, and prompt-conditioned TTS through a session-level runtime controller. The system uses incremental segment commitment to convert unstable ASR streams into translation-ready units, and an online speaker prompt manager to bind source speech spans to speaker-specific voice prompts for synthesis. We evaluate translation, speech quality, and latency with OpenSTBench, compare against proprietary speech translation APIs as behavioral baselines, measure long-form voice stability, evaluate speaker preservation in multi-speaker conversations, and assess multilingual translation quality. X-Translator provides an open platform for understanding the practical trade-offs of deployment-oriented S2ST. Code and demo are available at https://github.com/zhaoyx239/X-Translator.