# Grok TTS speech tags, tested: what <loud>, <singing> and [laugh] actually do

> Source: <https://dev.to/zhiwei_224e5e15600342dc0b/grok-tts-speech-tags-tested-what-and-laugh-actually-do-1jda>
> Published: 2026-11-01 03:02:49+00:00

xAI's Grok text to speech API (`POST https://api.x.ai/v1/tts`) has 28 built-in voices, 20 languages and a set of speech tags you put straight into the text. The docs list the tags; they don't say how much each one changes. I measured a couple.

``` js
const res = await fetch('https://api.x.ai/v1/tts', {
  method: 'POST',
  headers: {
    Authorization: `Bearer ${process.env.XAI_API_KEY}`,
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    text: 'Stand back. <loud>This is not a drill.</loud>',
    voice_id: 'eve',
    language: 'en',
    output_format: { codec: 'mp3', sample_rate: 24000, bit_rate: 128000 },
  }),
});
const mp3 = Buffer.from(await res.arrayBuffer());
```

`language` also takes `auto`. Price is $15 per million characters (xAI pricing page, checked 2026-10-30).

`[pause]`, `[long-pause]`, `[hum-tune]`, `[laugh]`, `[chuckle]`, `[giggle]`, `[cry]`, `[tsk]`, `[tongue-click]`, `[lip-smack]`, `[breath]`, `[inhale]`, `[exhale]`, `[sigh]`.`<soft>`, `<whisper>`, `<loud>`, `<build-intensity>`, `<decrease-intensity>`, `<higher-pitch>`, `<lower-pitch>`, `<slow>`, `<fast>`, `<sing-song>`, `<singing>`, `<emphasis>`.
Same sentence, voice Eve, English, one clip with and one without the tag. One clip each, so this is a quick check rather than a benchmark.

| Tag | Length | Loudness (RMS) | Median pitch | 
|---|---|---|---|
| none → `<loud>` | 5.5 s → 5.5 s | -20.7 → -20.9 dBFS | 195 → 253 Hz | 
| none → `<singing>` | 6.5 s → 8.4 s | — | 189 → 250 Hz | 

So `<loud>` is closer to "raised, urgent delivery" than a volume control: if you need a louder file, normalise it afterwards. `<singing>` stretches the words into a melody, which also makes the clip longer (and, on a per-character price, not more expensive).

If you want to hear the tags on all 28 voices before wiring up the API, I built a free front-end: [Grok Text to Speech](https://groktexttospeech.com/). The [speech tag reference](https://groktexttospeech.com/grok-tts-speech-tags/) has a before/after sample for each group, and there are preset pages for [whisper](https://groktexttospeech.com/whisper-text-to-speech/), [shouting](https://groktexttospeech.com/shouting-text-to-speech/) and [singing](https://groktexttospeech.com/singing-text-to-speech/). It's an independent project, not affiliated with xAI.