Agent Experience Designer, Voice (multilingual)

Sierra Sierra · AI Frontier · San Francisco, CA · Product Design

This role focuses on designing and scaling high-quality voice experiences for AI agents, improving voice quality, accelerating multilingual readiness, and creating more human-like interactions. The designer will evaluate voice providers, create evaluation frameworks, partner with engineering and product teams to resolve issues, and enable other teams to scale voice design effectively.

What you'd actually do

  1. Improve breadth and depth of voice quality: Evaluate, compare, and iterate on voices across multiple providers, languages, and use cases, ensuring experiences meet a high bar for clarity, naturalness, and appropriateness while continuously improving product and systems.
  2. Support faster multilingual readiness and launches: Partner with product, engineering, and deployment teams to research solutions, evaluate options, identify risks, and guide voice-related decisions that enable timely, high-confidence launches across regions.
  3. Design and apply effective and repeatable evaluations: Create and maintain structured methods for assessing voice performance and interaction quality, helping teams make informed tradeoffs and catch issues early.
  4. Partner cross-functionally to resolve voice and interaction issues: Collaborate with engineering, product, and support teams to investigate quality gaps, diagnose root causes, and drive improvements through clear recommendations and follow-through.
  5. Participate in customer-facing voice design work: Contribute to voice selection and design discussions with customers, helping them understand options, tradeoffs, and best practices while ensuring outcomes align with their goals.

Skills

Required

  • 5+ years in a role that blends product craft with applied systems thinking (e.g., voice/AI experience design, conversation design, applied linguistics, UX for AI, product engineering with strong user experience focus, localization program leadership with quality ownership)
  • Strong ability to operate across many languages and priorities—you bring structure to ambiguity and can ship reliably while quality stays high.
  • Experience creating repeatable evaluation frameworks (rubrics, test suites, scorecards, QA gates) and using them to drive decisions.
  • Excellent communication: you can turn messy signals into clear guidance for engineering, product, and customer stakeholders.
  • Comfort living close to the work: deep knowledge of the product, understanding our customers and our customers’ customers, always listening, digging into edge cases, constantly improving the system as well as the product.

Nice to have

  • Experience with speech synthesis and conversational agents.
  • Expertise with global language families.
  • Familiarity with provider and voice evaluation.
  • Linguistics, sound editing, and/or musical background.
  • Experience enabling other teams via playbooks, training, and internal tooling.

What the JD emphasized

  • 5+ years in a role that blends product craft with applied systems thinking
  • strong ability to operate across many languages and priorities
  • Experience creating repeatable evaluation frameworks
  • Excellent communication
  • Comfort living close to the work

Other signals

  • AI agents
  • voice experiences
  • multilingual readiness
  • evaluation frameworks