Google Gemini 3.1 Flash TTS Google · text-to-speech (TTS) API

Speed

Speko's board plots it at 851 ms time to first audio from US East; its model page reports a 978 ms sweep.

Voice quality

Speko rates its naturalness at 1,591 Elo from blind A/B votes on phone-agent lines (7th highest of the 43 models Speko rates). In the Artificial Analysis Speech Arena it holds 1,213 ±11 Elo (95% interval), 16th highest of the 98 models Artificial Analysis rates; scores whose intervals overlap are a tie. In its Customer Service category, Artificial Analysis places it 17th, at 1,242 Elo.

Numbers and dates

Speko's pronunciation test on numbers, dates and currency scores it 0.69 on a 0-to-1 scale (5th 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 $18.3. Speko lists about $33.3. List prices, as each source prints them: a range of $18.3 to $33.3.

Languages tested

Tested in Japanese, Chinese, Hindi, Korean, Filipino, Norwegian, Tamil, Telugu and Thai by Artificial Analysis or Speko. A language missing here was not tested, which does not mean it is unsupported.