Best text-to-speech API, by language
"Supports 30 languages" on a pricing page tells you nothing about whether a voice is intelligible, natively paced, or tonally correct in your language. We gate every system for intelligibility first, then publish the per-language measurements - including the systems that fail outright.
Thai
10/11 systems pass the intelligibility gateIndependent Thai TTS benchmark: 11 systems gated for intelligibility, then measured on rhythm (%V), tone fidelity, and anglicization. 1 system fails the Thai gate entirely.
Filipino
8/10 systems produce intelligible FilipinoIndependent Filipino (Tagalog) TTS benchmark: 10 systems checked for intelligibility, round-trip CER, pacing, and signal hygiene. 2 mainstream systems fail the Filipino gate by producing English.
Vietnamese
best system resolves 4/6 tonesIndependent Vietnamese TTS diagnostic: tone identification across all six Northern tones, including the glottalized ngã and nặng that pitch-only benchmarks miss. First run 2026-06-03.
Why only these languages?
We publish a language page only after the intelligibility gate has run for that language - ranking providers on a language we have not verified they speak would be exactly the kind of number this benchmark exists to kill. English, Indonesian, and Malay TTS pages will follow once their gates run; eval sets for all three already exist.