Google Gemini 3.8 Flash TTS Google · text-to-speech (TTS) API

Speed

Speko's board plots it at 1,010 ms time to first audio from US East; its model page reports a 1,031 ms sweep.

Voice quality

Speko rates its naturalness at 1,642 Elo from blind A/B votes on phone-agent lines (3rd highest of the 43 models Speko rates). In the Artificial Analysis Speech Arena it holds 1,278 ±14 Elo (95% interval), 5th highest of the 98 models Artificial Analysis rates; scores whose intervals overlap are a tie. In its Customer Service category, Artificial Analysis places it 3rd, at 1,345 Elo.

Numbers and dates

Speko's pronunciation test on numbers, dates and currency scores it 0.7 on a 0-to-1 scale (4th highest of the 30 models Speko scores). This is the accuracy measure used here; Coval's word error rate separates models too little to compare them.

Price

Artificial Analysis lists $16.5. Speko lists about $15. List prices, as each source prints them: a range of $15 to $16.5.

Languages tested

Tested in Spanish, German, French, Portuguese, Japanese, Chinese, Arabic, Hindi and Vietnamese by Artificial Analysis or Speko. A language missing here was not tested, which does not mean it is unsupported.