Feature Request: Add Vietnamese (vi-VN) support for voice mode

Summary

Voice mode in Claude Code does not support Vietnamese (vi-VN) as a dictation language. When attempting to use voice mode, Vietnamese is not listed as a supported language, and there is no way to customize or extend the supported language list.

Current behavior

• Voice mode shows: "Vietnamese is not a supported dictation language; using English."
• No configuration option exists to add Vietnamese support.

Expected behavior

Vietnamese (vi-VN) should be available as a supported dictation language in voice mode, similar to other languages.

Why this matters

Vietnamese is spoken by ~100 million people worldwide. Supporting it in voice mode would significantly improve accessibility and user experience for Vietnamese-speaking developers.

Environment

• Platform: macOS (darwin)
• Claude Code CLI

Request

Please add vi-VN (Vietnamese) to the list of supported dictation languages in voice mode.