Frontier evals for Voice AI

VoiceArena.com TTS Inline Steerability Leaderboard

Voice Arena™

TTS Inline Steerability

Early results
Methodology
Language
Track
Scoring
Voice
Text
RankCreatorModelTask Success Rate95% CI on Task Success Rate
0%20%40%60%80%
Tag AccuracyTierTags judgedPer-tag accuracy
LaughterExhaleCrywhisper●soft●loud●slow●fast●
1ElevenLabs
Eleven v4
eleven_v4
19.3%(all sets) · 300 sentences

15.2 to 24.1%

73.3%95% CI 71.4–75.1%
Inconsistent
2,20094%98%58%99%42%70%27%29%
2xAI
Grok TTS
grok-tts
14.3%(all sets) · 300 sentences

10.8 to 18.7%

52.9%95% CI 50.8–54.9%
Inconsistent
2,20092%91%45%44%14%6%6%8%
3Fish Audio
Fish Drama 3
drama-3
11.0%(all sets) · 300 sentences

7.9 to 15.0%

59.4%95% CI 57.3–61.4%
Inconsistent
2,20082%92%58%86%22%40%16%1%
4RResemble AI
Resemble Ultra
resemble-ultra
8.7%(all sets) · 300 sentences

6.0 to 12.4%

51.4%95% CI 49.3–53.5%
Inconsistent
2,20092%90%28%40%14%5%16%6%
5Inworld
Inworld TTS-2
inworld-tts-2
3.7%(all sets) · 300 sentences

2.1 to 6.5%

74.0%95% CI 72.1–75.8%
Inconsistent
2,20097%90%4%24%58%89%92%74%
6Fish Audio
Fish S2.1 Pro
s2.1-pro
0.0%(all sets) · 300 sentences

0.0 to 1.3%

18.3%95% CI 16.8–20.0%
Unreliable
2,20039%41%0%0%1%2%0%0%

Models are ranked by Task Success Rate; models with the same Task Success Rate share a rank.

This is the ranked measure. Every tag was decided by a majority of five independent listeners — at least three of the five had to mark it correct — and laugh, chuckle and giggle count as one sound, as do sigh and breath. This is the only way of scoring these clips that listeners agree on well enough to rank.

Task Success Rate always uses the ranked measure. It is the share of sentences in which every ranked tag was correct.

The Gemini models document all six event sounds as inline tags, but document no way to hold a style across a chosen run of words — Google’s method is a style setting that covers a whole turn. Our style spans sit inside one sentence, so these models appear on the Events set alone.

Draft · internal review copy: five listeners per clip, majority decision. Not yet published.

See what a listener saw

This is the screen a listener works on. Play the clip, read the transcript, and answer one question for every marked span — how the words were said, and whether anything went wrong. Try it yourself: the options below are live.

0:000:15
Marked words — the model was told to say these in a particular way

1I made coffee this morning, and the kids left early, because 2the bus came at seven fifteen. Then the clinic called, and 3the doctor said Dad's test came back fine, and then 4I called Aunt May, 5she's coming in June, and we booked the dinner.

SPAN 1How were all of the words in span 1 said?
“I made coffee this morning,”
WhisperedSoftLoudSlowFastSaid normally
Is there a problem with this span?
No problemPartial (only some words)Carried on past the spanRead out as wordsGarbled / glitchyOther
SPAN 2How were all of the words in span 2 said?
“the bus came at seven fifteen.”
WhisperedSoftLoudSlowFastSaid normally
Is there a problem with this span?
No problemPartial (only some words)Carried on past the spanRead out as wordsGarbled / glitchyOther
SPAN 3How were all of the words in span 3 said?
“the doctor said Dad's test”
WhisperedSoftLoudSlowFastSaid normally
Is there a problem with this span?
No problemPartial (only some words)Carried on past the spanRead out as wordsGarbled / glitchyOther
SPAN 4How were all of the words in span 4 said?
“I called Aunt May, she's coming in June, and we booked the dinner.”
WhisperedSoftLoudSlowFastSaid normally
Is there a problem with this span?
No problemPartial (only some words)Carried on past the spanRead out as wordsGarbled / glitchyOther
SPAN 5How were all of the words in span 5 said?sits inside span 4
“she's coming in June,”
WhisperedSoftLoudSlowFastSaid normally
Is there a problem with this span?
No problemPartial (only some words)Carried on past the spanRead out as wordsGarbled / glitchyOther

A real clip from the run — 5 style spans, 16 seconds.

About TTS Inline Steerability

A text-to-speech model is increasingly asked to do more than read a sentence. It is asked to laugh in one place, sigh in another, and drop to a whisper for six words before returning to a normal voice. Those instructions are written into the text itself as inline tags.

The question this leaderboard answers is simple: when a model is given an inline tag, does it perform that tag — the right one, in the right place, without damaging the rest of the sentence?

How it works

  1. A sentence is written once, in a vendor-neutral notation, carrying tags at planned positions — a point tag such as {laugh}, or a span such as {whisper}…{/whisper}.
  2. An adapter rewrites each tag into the exact string that vendor documents. No model is given a substitute for a tag it does not support, and no sentence is written for a particular model.
  3. Every model generates the same sentences. Five different people listen to each clip, independently, and for each tag say what they actually heard — choosing from the six sounds, or nothing there, read out as words, garbled, or another sound. Nobody hears the same clip twice.
  4. A tag scores a point when at least three of the five listeners agreed it was right. One person’s opinion never decides a tag.

Events and styles

An event is a sound at one point in the text: laugh, chuckle, giggle, sigh, breath, cry. A style is a delivery held across a run of words: whisper, soft, loud, slow, fast. Sentences come in three sets, each ranked on its own, because a model that is good at one is routinely poor at another.

What the controls do

Four switches above the table. Each one changes which answers are counted, never how they were graded.

ControlSettingWhat it means
Trackwhich sentences are scoredAll setsAll three sets together.
EventsSentences carrying six sound tags and nothing else.
StylesSentences carrying five style spans and nothing else.
MixedSentences carrying both — six sounds and five spans in one sentence, eleven tags in all. The hardest set for every model here.
Scoringhow strictly an answer is markedExact tagThe listener must name the exact sound. Told {chuckle}, only “chuckle” counts — “laugh” and “giggle” are wrong.
Same familyA neighbouring sound counts. Laughter = laugh, chuckle, giggle. Exhale = sigh, breath. Cry stands alone, so its score never changes. Style spans score identically in both modes, because a whisper is not a near-miss for “fast”. Nothing there, read out as words and garbled are wrong in both.
Textwhat the words around the tag are doingAllEvery sentence, both kinds below.
NeutralThe words agree with the tag — a {chuckle} placed on something that is actually funny.
Fights the tagThe words pull the other way — a {chuckle} on “there is nothing funny about this”. It tests whether the model follows the instruction it was given or the mood of the sentence. Half the sentences in the run are written this way.
Voice / LanguageFemale / MaleWhich voice generated the clip. Voices were fixed before any audio was heard.
US EnglishThe only language in this run.

What each column means

ColumnWhat it tells you
Rank1 (1–2)The position, then the range that position could plausibly take. 1 (1–2) means the model could honestly be first or second; 5 (5–5) means its place is not in doubt. Two models sharing a rank number are statistically tied — the difference between them could be chance.
Tag AccuracyThe headline. Out of every individual tag the model was given, the share it performed correctly. Higher is better.
95% CIHow far the score could move if the eval were run again on a fresh set of sentences. The dot is the score, the bar is the range. Where two bars overlap heavily, the gap between those models is not yet evidence of anything — which is why they share a rank.
Task Success RateA much harder test: the share of sentences in which every single tag was correct. One tag wrong anywhere and the whole sentence fails. The letter under the number says which set it covers — (E) Events, (S) Styles, (M) Mixed, or (all sets) for every sentence pooled together. Pick a set in Track to see that set on its own. The sets are not equally hard: a sentence carries 6 tags in Events, 5 in Styles and 11 in Mixed, so a Mixed sentence is far harder to get whole.
TierThe plain-English version of the score. Reliable — performs the tag correctly at least five times in six, so a product can depend on it. Inconsistent — between half and five-in-six. Unreliable — below half.
Tags judgedHow much evidence sits behind the row. More tags means a narrower confidence interval.
Per-tag accuracyThe same tag-accuracy figure broken down one tag at a time, so you can see which specific instructions a model handles. Which tags appear follows the Track and Scoring switches: six sounds on Events, five styles on Styles, all eleven elsewhere, or the three sound families in same-family scoring. Green is 60% or above, amber 35–60%, red below 35%.

The eleven tags

A tag only enters this list when at least three vendors document it. Emotion styles such as angry or sad are left out of this version, because judging them needs an opinion about emotion rather than a yes-or-no about a sound.

TagTypeWhat it asks the model to do
{laugh}EventFull, voiced laughter with several pulses.
{chuckle}EventA short, soft, mostly closed-mouth laugh.
{giggle}EventA light, quick, higher-pitched laugh.
{sigh}EventA long audible exhale carrying emotion — tired, relieved, resigned.
{breath}EventAn audible breath: catching your breath, or a breath before going on.
{cry}EventA short burst of weeping.
{whisper}…{/whisper}StyleAn unvoiced whisper across the span.
{soft}…{/soft}StyleQuiet but still voiced.
{loud}…{/loud}StyleRaised volume, not a scream.
{slow}…{/slow}StyleA noticeably slower speaking rate.
{fast}…{/fast}StyleA noticeably faster speaking rate.

A model that does not document a tag is never sent its sentences and never given a substitute, so it is not ranked on a set where it is missing tags. The two Gemini models document all six event sounds as inline tags, but document no way to hold a style across a chosen run of words: Google’s documented method is a style setting that covers a whole turn, and its own guidance for a change mid-sentence is to split the script into separate turns. Our style spans sit inside one continuous sentence, so these models appear on the Events set alone.

The hardest tags

Accuracy on each tag, averaged over every model that was sent it. The dashed line on the event bars marks 10%: what a listener would score by guessing, since the event question offers ten options.

Sounds, ranked scoring

fast
20%
cry
25%
soft
25%
slow
26%
loud
35%
whisper
49%
breath
75%
chuckle
76%
giggle
80%
laugh
81%
sigh
89%
0%20%40%60%80%100%

Styles, ranked scoring

fast
20%
Cry
25%
soft
25%
slow
26%
loud
35%
whisper
49%
Laughter
79%
Exhale
82%
0%20%40%60%80%100%

Sounds, exact (not ranked)

giggle
6%
fast
20%
chuckle
22%
laugh
24%
cry
25%
soft
25%
slow
26%
loud
35%
breath
37%
sigh
48%
whisper
49%
0%20%40%60%80%100%

Cry is the broken one at 25% even under the ranked measure, and it is the only sound with no family to fall back on. The right-hand column shows what happens when the exact word is demanded instead of the family: every sound collapses, which is the disagreement between listeners showing up as a score.

Results

Model-and-tag pairs now good enough to use

29 of 78

One listener and exact-wording scoring put this at 1 of 78. Five listeners and family scoring put it at 29. 4 models reach the Reliable tier on the Events set.

The top two cannot be separated

74.0% vs 73.3%

Inworld TTS-2 and Eleven v4 are statistically tied for first on tag accuracy across all five rounds (McNemar, p ≥ 0.05). They are not tied on the tracks: Inworld leads Styles, Eleven v4 leads Events.

The two leaders are not interchangeable

99% vs 24%

Eleven v4 performs whisper at 99% and Inworld at 24%. On slow it is the other way round, 27% against 92%. Which one is right for you depends on which tags you send.

Exact wording still cannot be ranked

0.65

Five listeners agree on which exact sound they heard only 0.65 of the way to perfect agreement, still below the 0.667 needed. Laughter can be measured; which kind of laughter cannot.

Tag accuracy by set

The share of individual tags performed correctly.

ModelEventsStylesMixedAll sets
Inworld TTS-278.5%69.2%73.7%74.0%
Eleven v490.8%53.8%72.5%73.3%
Gemini 3.8 Flash TTS59.7%––59.7%
Fish Drama 384.0%31.4%58.6%59.4%
Gemini 3.8 Flash-Lite TTS59.2%––59.2%
Grok TTS87.8%17.8%49.7%52.9%
Resemble Ultra85.0%18.0%48.3%51.4%
Fish S2.1 Pro35.0%0.8%17.2%18.3%

Task Success Rate by set

The share of sentences where every tag was correct. Reported per set and never pooled, because a sentence carries 6 tags in Events, 5 in Styles and 11 in Mixed.

ModelEventsStylesMixed
Inworld TTS-22.0%9.0%0.0%
Eleven v451.0%5.0%2.0%
Gemini 3.8 Flash TTS0.0%––
Fish Drama 333.0%0.0%0.0%
Gemini 3.8 Flash-Lite TTS0.0%––
Grok TTS43.0%0.0%0.0%
Resemble Ultra26.0%0.0%0.0%
Fish S2.1 Pro0.0%0.0%0.0%

Supporting measures

None of these affect the ranking.

ModelClean speechWords matchScoreTags with all five rounds
Inworld TTS-297.3%99.3%74.0%94%
Eleven v496.6%100.0%73.3%97%
Gemini 3.8 Flash TTS90.9%97.0%59.7%98%
Fish Drama 398.7%100.0%59.4%95%
Gemini 3.8 Flash-Lite TTS96.0%100.0%59.2%99%
Grok TTS99.3%98.0%52.9%94%
Resemble Ultra97.7%98.3%51.4%95%
Fish S2.1 Pro96.3%99.3%18.3%92%

Appendix

Showing: US English · All sets

English only. Every clip generated once per model from the same script, with voices fixed before any audio was heard.

71,172 listener judgements on 14,400 tags over 2,000 sentences by 250 listeners over 5 rounds · job 1635 · last updated 2026-11-06.