Sierra launches 𝜏-i18n multilingual voice agent evaluation benchmark
Sierra releases 𝜏-i18n, extending 𝜏-Voice to five languages: Spanish, Brazilian Portuguese, Hindi, Korean, and Mandarin, retaining the same airline, retail, and telecom tasks, policies, tools, and success criteria to enable cross-language comparison. Across 2,700 main calls, task completion rates for Spanish, Hindi, and Portuguese lag English by an average of 2.4, 3.8, and 6.4 percentage points, while Korean and Mandarin lag by 22.6 and 9.1 percentage points respectively; Korean is the weakest language among the three agents. In addition to task completion, 𝜏-i18n separately reports interaction metrics (response timing, selectivity, tool-call efficiency) and generation quality (naturalness, speech fidelity), and has open-sourced the codebase and the language pack framework LanguageFactory.

Sierra releases 𝜏-i18n, extending 𝜏-Voice to five languages: Spanish, Brazilian Portuguese, Hindi, Korean, and Mandarin, retaining the same airline, retail, and telecom tasks, policies, tools, and success criteria to enable cross-language comparison. Across 2,700 main calls, task completion rates for Spanish, Hindi, and Portuguese lag English by an average of 2.4, 3.8, and 6.4 percentage points, while Korean and Mandarin lag by 22.6 and 9.1 percentage points respectively; Korean is the weakest l
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