Information-Transport-based Policy for Simultaneous Translation
Shaolei ZhangYang Feng
Proposes an optimal-transport-inspired policy for simultaneous translation that explicitly quantifies received source information to make accurate read-write decisions across text and speech streaming benchmarks.
Real-time communication tools such as live broadcasting, online subtitling, and international conferencing increasingly rely on simultaneous translation systems that translate incoming text or speech in real time. The central technical challenge is balancing translation quality against delay: the system must decide whether to generate the next translated word immediately or wait for more incoming source content. Previous approaches either followed rigid timing rules that produced premature and inaccurate translations or used adaptive models that made timing decisions without directly evaluating whether the received context contained enough information to translate accurately.
The article demonstrates a new framework called Information-Transport-based Simultaneous Translation to solve this trade-off. The main objective was to develop and evaluate a translation policy that explicitly measures the flow of information from incoming source units to target words, triggering translation only when a sufficient proportion of required source information has arrived.
To achieve this, the authors treated translation as an information transport process constrained by both translation accuracy and latency costs. They implemented an information-transport-based policy alongside an easy-to-hard curriculum training method that trains a single universal model to operate under arbitrary latency requirements. The authors evaluated the approach across both text-to-text benchmarks (English-to-Vietnamese and German-to-English) and streaming speech-to-text datasets (English-to-German and English-to-Spanish), comparing it against fixed and adaptive baseline systems across multiple translation quality and latency metrics.
The evaluation yielded several key findings. First, the proposed framework consistently outperformed existing state-of-the-art methods across all evaluated latency ranges in both text and speech translation. Second, in low-latency speech translation scenarios with latency under 1,000 milliseconds, the framework improved translation quality scores by roughly 10 points compared to standard baseline systems. Third, the policy captured approximately 5% more correctly aligned source words before translating under low latency, reducing premature word generation. Fourth, the curriculum training schedule successfully trained a single model capable of performing well across all latency settings without requiring separate models for each delay target. Finally, incorporating information transport modeling directly improved full-sentence, non-simultaneous text and speech translation benchmarks by up to 1 quality point.
These results demonstrate that explicitly tracking information sufficiency substantially improves translation faithfulness while avoiding unnecessary waiting delays. Operationally, replacing multiple latency-specific models with a single universal model reduces system training costs, computational resource demands, and maintenance overhead. The improved handling of word-order differences and speech segment boundaries makes real-time automated interpretation more viable for mission-critical and latency-sensitive deployments.
For practical implementation, organizations deploying real-time translation systems should adopt information-sufficiency policies over rigid timing heuristics and use the single-model curriculum training approach to reduce operational complexity. Before broad enterprise deployment, teams should conduct real-time pilot tests to tune latency thresholds for specific domain requirements and computing hardware constraints.
While the empirical results demonstrate strong confidence across standard benchmarks, the authors note that modeling information transport relies on joint learning with attention mechanisms that could be further refined. Future work should evaluate more fine-grained source contribution analyses while ensuring that additional computational overhead does not increase real-time decoding delays.
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