= /v1/tts/voices の別名（要キー）

GET 
/v1/audio/voices

= /v1/tts/voices の別名（要キー）

Responses

200

OK

401

401 — code: invalid_user_token / not_authenticated / unauthorized

429

429 — code: ip_daily_cap / rate_limited / user_daily_cap

500

500 — code: internal_error