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Episode 6147 manual-script

Hebrew AI: Ears, Mouth, and Brain

Open Hebrew speech recognition beats the paid services. Hebrew text-to-speech is a different story — and the language models are a third.

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The prompt

The prompt that started this episode, as sent in (production notes for the hosts removed).

Hannah has started using Whisperian (whisperian.app), an offline ASR app I've recommended before, which nicely decouples transcription from post-processing. Looking at my English-Hebrew code-switching app, she asked whether there's a Hebrew speech-to-text model. I explained the problem multilingual models have with Hebrew, and said I was almost certain I'd seen open-source Hebrew ASR models, more sure about Hebrew TTS, and that Hebrew-native LLMs exist, but I wasn't totally sure. We've touched on parts of this before; this is the one overarching episode: what Hebrew-native models actually exist right now, closed and open-weights, in speech-to-text, text-to-speech and LLMs, and how good are they?

The question started simply: does anyone actually build AI for Hebrew, or are we all watching English models do an impression of it? The answer depends on which part of the system you mean — ears, mouth, or brain — and each modality has its own twist.

For speech recognition, the name to know is ivrit.ai, an Israeli project whose flagship model is a fine-tune of Whisper large v3 turbo under an Apache 2.0 license, trained mostly on roughly 4,700 hours of Knesset plenum recordings plus a few hundred hours of crowd-transcribed audio. The organization runs a public Hebrew transcription leaderboard updated this month, averaging word error rate across five test sets. Top of the board is an ivrit.ai build at about 8.8 percent, followed by the turbo build at 9 percent and the commercial service Soniox at 9.9 — the best commercial entry. Amazon Transcribe sits near 11.5, plain Whisper large v3 around 14.5, and OpenAI's GPT-4o transcribe near 18, hitting 39 percent on one broadcast test set. The lesson is blunt: fine-tuning on Hebrew roughly halves the error of the model it started from. Scale didn't win. Hebrew data won.

Running it offline is possible through faster-whisper and ONNX builds, though a Hebrew ggml build couldn't be confirmed — and a similarly named Yiddish model family is an easy trap. A tiny 66-million-parameter streaming model called zipformer runs in-browser via WebGPU and still beats Amazon on average. Caveats apply: newer commercial models aren't in the table, and two test sets belong to ivrit.ai itself.

Text-to-speech tells a different story. On ivrit.ai's blind-listening TTS arena, the top of the field is entirely closed: Google's Gemini 3.1 Flash TTS leads, followed by Israeli company Deepdub and ElevenLabs v3. The first non-proprietary entry lands ninth, roughly a hundred Elo points back. The open side rides on Phonikud, a Hebrew grapheme-to-phoneme system that resolves written ambiguity into full IPA with stress marks before a voice model ever sees the text — potentially letting a small local model approach large proprietary systems with as little as an hour of Hebrew fine-tuning data. Usable models built on that line include LightBlue and Blue v3, both MIT licensed.

Mentions

  • Deepdub Israeli AI voice and dubbing company
  • DictaLM 3.0 Hebrew LLM family from DICTA
  • Hebatron Hebrew mixture-of-experts LLM from HebArabNlp
  • ivrit.ai Open Hebrew speech dataset project
  • LightBlue Hebrew-first open TTS model
  • Phonikud Open-source Hebrew grapheme-to-phoneme model
  • Soniox Commercial speech recognition service
  • Whisper large-v3 OpenAI multilingual speech recognition model
  • Whisper-Hebrish Hebrew-English code-switching Whisper fine-tune
  • zipformer Small streaming speech recognition model

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#6147: Hebrew AI: Ears, Mouth, and Brain

Corn
Does anyone actually build AI for Hebrew, or are we all watching English models do an impression of it?
Herman
Ears, mouth or brain? The answer is different for each, and that's the fun of it.
Corn
Hannah asked it from the ears side. She's started using Whisperian, the offline transcription app Daniel has recommended before, the one he likes because it keeps transcription separate from post-processing. She was looking at his English and Hebrew mixed-speech app and asked whether there's a Hebrew speech-to-text model at all. Daniel gave her the reasons the big multilingual models struggle with Hebrew, then admitted he's nearly sure he's seen open-source Hebrew speech recognition, more sure about Hebrew text-to-speech, and he knows there are Hebrew-native language models. But he wouldn't swear to any of it. So what exists as of now, open and closed, and how good is it?
Herman
His hunches are right on all three. Open Hebrew speech recognition exists, Hebrew speech synthesis exists, Hebrew language models exist. What I like is that each one comes with a twist he didn't mention, and the twists are different in each modality.
Corn
Ears first, then.
Herman
Ears first. The name to know is ivrit.ai. It's an Israeli project, and its flagship is a fine-tune of Whisper large version three turbo, Apache two point oh licence, trained in April of last year. The training data is mostly the Knesset plenum recordings, about four thousand seven hundred hours of them, plus a few hundred hours of crowd-transcribed audio.
Corn
Four thousand seven hundred hours of the Knesset. Half a year of people interrupting each other.
Herman
Which is a surprisingly good training set, actually, because it's long, it's real speech, and it has every register from formal to furious. Now, how good it is. The organisation runs a public Hebrew transcription leaderboard, updated this month, that averages word error rate across five test sets. Top of the board is an ivrit.ai build at about eight point eight percent. Second is the turbo build at about nine percent. Third is Soniox, a commercial service, at about nine point nine, and that's the best commercial entry.
Corn
A small open fine-tune beating the paid services. I'd have bet the other way.
Herman
Most people would. Now look at what's underneath. Amazon Transcribe is around eleven and a half. Plain Whisper large version three, the thing everybody actually runs, is about fourteen and a half. Deepgram's Nova three is about fourteen point six.
Corn
So fine-tuning on Hebrew roughly halves the error of the model it started from?
Herman
Close to it, going from the plain large version three number to the ivrit.ai one. It's the whole story in one comparison, really. Scale didn't win. Hebrew data won.
Corn
Hebrew data over scale. I'd put that on a mug.
Herman
The data being public is half the reason this works, by the way. The Knesset recordings, the crowd-transcribed sets, the evaluation sets, the WhatsApp-style one, they're all published as datasets. The original paper from twenty twenty-three counted over three thousand three hundred hours of Hebrew speech, and the collection has grown since. So anyone can fine-tune from the same starting point, and some people have.
Corn
Public data, public models, a leaderboard they run themselves. That's a very tidy little ecosystem for a language with a small market.
Herman
Small market, very motivated people. I think that's the whole recipe.
Corn
Where do the big names land?
Herman
Further down. ElevenLabs Scribe version one is about sixteen and a half. OpenAI's GPT four oh transcribe is about eighteen, and on one of the test sets, the Kan broadcast one, it hits thirty-nine percent. The mini version is about twenty-three. Google Speech is twenty-eight point six.
Corn
Google Speech at nearly thirty percent. For a language with that many native speakers on their doorstep.
Herman
Bottom of the table is NVIDIA's Nemotron three point five streaming model, used zero-shot, so with no Hebrew training, at about thirty-five and a half. Deepdub, the Israeli voice company, took that same model family and fine-tuned it on its own Hebrew data, and it says the result is good. That's their number, not an independent one.
Corn
Thirty-five percent. That's less transcription than a rough guess.
Herman
There are caveats on the table, and they matter. The newer commercial models aren't in that table: Scribe version two, the newer Gemini audio, Chirp three. And two of the test sets are ivrit.ai's own, so a home-advantage effect is possible. I'd say the ranking among the open models is solid and the exact gap to the commercial ones is softer than it looks.
Corn
ElevenLabs advertises Hebrew speech recognition, doesn't it? I remember a number that looked very good.
Herman
Their own Hebrew page quotes about three percent on the FLEURS set. The same page also shows fifteen. From what I can tell, the page disagrees with itself, so I wouldn't build anything on it.
Corn
Three or fifteen. I'd go with the one that matches the leaderboard.
Herman
Now the part Hannah cares about, which is running it offline. ivrit.ai publishes faster-whisper builds and an ONNX build of the turbo model, both on its Hugging Face page. I'd have guessed a ggml build too, for the llama-dot-cpp style runtimes, but the only ones I saw on the page were for the Yiddish models. So I can't confirm a Hebrew ggml build.
Corn
Hold on, Yiddish?
Herman
That's the twist. There's a family called yi-whisper in the same organisation. It sounds like it could be a Hebrew thing. It's Yiddish, a different language with its own training data. Anyone grabbing the wrong checkpoint because the name looked right is going to have a strange afternoon.
Corn
Yi, as in the thing you say when your transcript comes out in the wrong language.
Herman
There's also a small one worth knowing about, a streaming model called zipformer, sixty-six million parameters. It runs in a browser through WebGPU, it's CC-BY licensed, and it scores about five percent on one of the test sets and nearly nine on the WhatsApp-style one. Averaged across the leaderboard it's eleven point one, which still beats Amazon.
Corn
Sixty-six million. That's smaller than most phone keyboards' prediction models, I'd guess.
Herman
I wouldn't swear to that comparison, Corn. But it was originally built by one developer, Yakov Kolani, and ivrit.ai adopted it. Which is a nice reminder of how much of this scene is a handful of people.
Corn
Daniel's one of them, in a small way. His Whisper-Hebrish took the turbo model from about seventeen percent to about six on his own mixed-language set. That set is small, so it's his number for his voice, not a benchmark.
Herman
His Parakeet fine-tune for code-switching was the same instinct on a different base model. And that's relevant, because NVIDIA does not have an official Hebrew Parakeet. Parakeet version three, as far as I know, is a European-language model. Hebrew isn't in it.
Corn
Which matters, because Parakeet is what Whisperian's local engine runs.
Herman
It does, along with the cloud options through your own API keys. Keep that in your pocket for the end.
Corn
Do you think the home-advantage worry is serious, Herman? Or is that me being a sloth about it?
Herman
Less serious than it sounds, I think. The Knesset data and the eval sets are different audio. But I'd want to see someone outside ivrit.ai run the same test. There's a model called GigaAM-He whose card has its own side-by-side where the ivrit turbo model still comes out ahead. I only saw that through a search snippet, though, so treat it as a hint.
Larry
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Corn
...so what I'd actually want to know is whether the ivrit.ai number survives a bad microphone.
Herman
The WhatsApp set is exactly that. Noisy, compressed, people talking over each other, and every system gets worse on it, which is why it's the one I'd watch.
Corn
Mouth, then. I'm braced for this being a shorter and sadder story.
Herman
Shorter, and not sad. Just a different shape. In speech recognition, the open model is on top. In Hebrew speech synthesis, the top of the arena is all closed models.
Corn
There's an arena?
Herman
ivrit.ai runs a Hebrew TTS arena, blind listening votes turned into Elo ratings. I read it today. In first place is Google's Gemini three point one Flash TTS at about fifteen hundred and eighty-seven. Second is Deepdub, an Israeli company, at about fifteen seventy-four. Third is ElevenLabs version three at fifteen fifty-two.
Corn
You read that table out like a racing commentator.
Herman
Someone has to. Deepdub being Israeli makes second place feel like a home game, but it's a blind vote. Fourth is Soniox, fifth is OpenAI's realtime model at about fifteen hundred. And then the first entry that isn't labelled proprietary is ninth, Blue version two, at about fourteen seventy-four. That's roughly a hundred points behind the leader. I'm inferring it's open from the labelling, not from the page saying so, and the vote counts aren't shown, so I'd read it as a general shape.
Corn
A hundred points of Elo. In human terms?
Herman
Listeners would pick the leader most of the time, but not overwhelmingly. And ninth place there is still above OpenAI's older TTS models, which sit around fourteen forty-five.
Corn
Ninth out of a field with Google and ElevenLabs in it. I'd call that a podium of sorts.
Herman
The open side rides on one idea. A project called Phonikud. It's a Hebrew grapheme-to-phoneme system, meaning it turns written Hebrew into a precise pronunciation, full IPA with stress marks, built as adaptors on top of a diacritizer. It's being presented at Interspeech this year. The code is CC-BY, though the training datasets are non-commercial, which matters if you want to build a product on it.
Corn
So it solves the problem Daniel described in the prompt, upstream of the voice.
Herman
Yes, and that's the neat bit. The ambiguity, that the same written letters can be several different words, is resolved before the voice model ever sees the text. The claim from the authors is that a small local voice model fed Phonikud phonemes gets close to large proprietary systems, and that you can fine-tune an English model on about an hour of Hebrew if you give it those phonemes. That's their claim, mind you. A follow-up called ReNikud came in June, and I've only seen its abstract.
Corn
An hour of Hebrew. I've napped longer than that.
Herman
And you'd have made less progress. The usable models built on this line are LightBlue, which is Hebrew-first with English and MIT licensed, and Blue version three, which is Hebrew-first multilingual, also MIT. LightBlue's developer claims twelve hundred and sixty times real time on an RTX three thousand ninety, and thirty-five times real time on a plain CPU. Self-reported. Blue version three is a flow-matching model at forty-four point one kilohertz, and the card has no quality numbers at all.
Corn
Thirty-five times real time on a CPU. So I could synthesise this episode while I'm reaching for my tea.
Herman
With a long reach. The release dates aren't clear to me, LightBlue looks to be around eight months old. There's also a sibling called blue-yi, and yes, that's Yiddish again.
Corn
Same trap, new directory.
Herman
One more thing about the arena. ivrit.ai published the preference data from all those blind votes as its own dataset, updated just a few days ago. So the open Hebrew TTS people get a free scoreboard and the raw votes to learn from. That's a loop the closed vendors don't get to use in public.
Corn
Voting in public, with the ballots published. Closed vendors can't copy that without opening their ballot box.
Herman
What would you use, Corn? If you were building something that speaks Hebrew tomorrow.
Corn
Honestly, for a personal project I'd start with the open one. Local, free, and I can fix it myself when it mispronounces something. If it were going out to customers who'll judge the voice in four seconds, I'd pay for one of the top four.
Herman
Same split I'd draw. And Azure has Hebrew neural voices, Hila and Avri, which I've only seen listed on a third-party page, not Microsoft's own. So I'd check that before leaning on it.
Corn
Brain, then. Everyone's favourite.
Herman
This one has two entrants, and they're a little bit rivals. First, DictaLM three point zero, from DICTA, an Israeli nonprofit. It launched in December, with the paper out in February. Three sizes: twenty-four billion built on Mistral Small, twelve billion on NVIDIA's Nemotron Nano, a hybrid state-space design, and one point seven billion on Qwen three. Each comes in base and instruct or thinking flavours, with tool calling and a sixty-five thousand token context.
Corn
Which is the one I can try without owning a datacentre?
Herman
The twenty-four billion has a hosted chat page run by DICTA. There are quantised versions too, listed as updated in May, which should bring it within reach of a decent graphics card. The training recipe is about a hundred billion Hebrew tokens and thirty billion English, mixed roughly three to one, so it doesn't forget English. Press coverage says Apache two point oh licence, but I haven't seen the model card say it.
Corn
How good is it? I'm assuming there's a table with a lot of bold numbers.
Herman
There is, and it's honest about what it measured. On Hebrew chat tasks, the twenty-four billion thinking model gets about fifty-seven on summarisation, where Gemma three twenty-seven billion gets about forty-five and Llama three point three seventy billion gets about thirty-eight. Translation, trivia, same direction. Then there's a vowel-pointing task. DictaLM scores about eighty-seven. Llama's seventy billion scores about four.
Corn
Four. Out of a hundred. That's the model knowing it's Hebrew but declining to try.
Herman
That is how task-specific it gets. A model can read your Hebrew perfectly well and be hopeless at one operation on it. And it isn't a clean sweep. On the Winograd-style reasoning set, Llama seventy billion wins, about eighty-three against about seventy-eight.
Corn
Good. I trust a table more when the home team loses one.
Herman
The small model is the part that surprised me. The one point seven billion DictaLM scores about ten on summarisation. Qwen three at the same size, the model it was built from, scores under one. On translation it's about two against zero.
Corn
Ten out of a hundred is still a bad grade. But it's the difference between a bad grade and not turning up.
Herman
And on the vowel task, fifty-three against three. A model that size fits on a laptop, Corn. Would you run a Hebrew model locally if it were that small, or is it still too weak to bother?
Corn
For cleaning up a transcript, maybe, if the cleanup is simple. For anything I'd want to trust with a nuance, I'd go up to the twelve or the twenty-four. Small models are for tidying, not thinking.
Herman
That's roughly where I'd land.
Corn
Fair. I'd still like to know who the table left out.
Herman
Here's what the table doesn't have, though. Only open models are compared. Gemini two point five Pro appears as a reference for win-rates, and GPT four oh is the judge, but there's no row where a frontier closed model sits next to DictaLM on the same benchmark. I couldn't find that head-to-head anywhere, and I'm not going to invent a ranking.
Corn
So if someone says the closed frontier models beat it, or that it beats them, that's a feeling, not a measurement.
Herman
Right now, yes. The second entrant is Hebatron, from a project called HebArabNlp. Thirty-one point six billion parameters total but only about three billion active at a time, a mixture-of-experts design, built on NVIDIA's Nemotron three Nano. It was made by PwC Israel and MAFAT, the national NLP program, with AWS. Apache two point oh. About ninety-nine billion training tokens, three and a half billion of them colloquial Hebrew, and around two million instruction samples.
Corn
A government-backed rival to the nonprofit. That's a sentence I didn't expect to say out loud today.
Herman
The authors claim a Hebrew reasoning average of seventy-three point eight against DictaLM's sixty-eight point nine, and about nine times the throughput, which follows from only three billion active parameters. Those are their own figures, from a paper in May. I haven't seen an outside group repeat them.
Corn
The two are on the same leaderboard, I take it, since MAFAT and DICTA both back it.
Herman
They do co-run a Hebrew LLM leaderboard. Tasks like natural language inference, question answering, sentiment, Winograd, translation and Israeli trivia. I couldn't load the rows, so I can't tell you whether any closed models are on it.
Corn
Daniel said he knew of Hebrew-native LLMs. I assume he meant these.
Herman
Probably. One more name for completeness. AI twenty-one's Jamba one point five officially supports Hebrew, and their CEO told Calcalist that Hebrew is not a significant market. It's now a legacy model.
Corn
Not a significant market, said an Israeli company. I'd have chosen different words in an interview.
Herman
The practical backdrop for all of it is the tokenisation tax. One blog post from July measures Hebrew at about one and a third times the tokens of English on OpenAI's newer tokenizer, close to two times on Claude's, and around four times on the old GPT four one. Blog-level numbers, not rigorous. Whether DictaLM's tokenizer fixes that, the paper doesn't say.
Hilbert
...and Pinchas says it's the nine-metre one, same as last month, and I say Pinchas, I paid for the nine-metre one in March. He says that was the other nine-metre one. He keeps two.
Herman
Two nine-metre cables, same shop?
Hilbert
Same counter. Hillel Street, two doors from the pharmacy. Six and a half months, by the way. The Knesset hours. Not half a year. A hundred and ninety-six days if you ran it without stopping.
Corn
You counted that.
Hilbert
Before the first break. The rule is the microphone sits in the kitchen and the laptop sits in the stairwell, on the third step, and between them is nine metres of cable, no more, no less. Eight is too close. The Hebrew comes out soft. Pinchas has sold me cable for nineteen years and he has never once sold me a ten.
Herman
Nine metres from the kitchen to the third step. That's a long run for a microphone signal, but the loss is small.
Hilbert
Herman, you said leaderboard eleven times. I cut two. The step belongs to Pinchas's sister-in-law. Forty shekels a day, and the laptop has its own tenancy, with a clause about Purim.
Corn
Does she check the cable?
Hilbert
Every morning at seven. She measures it with a tailor's tape. Corn, you're peaking on the b's, I'll ride it down. Anyway, Pinchas rents me the cable by the hour. Nine shekels. He keeps it in the shop between uses, in a biscuit tin with my name on it, next to the offcuts of every cable he's ever cut for me, which he also charges for. Eleven years of offcuts. They're in the tin.
Herman
He bills you for cable you didn't use.
Hilbert
And for the tin. I record everything with the phone in my shirt pocket, though. That's Pinchas's other rule. He says nobody in the history of speaking has talked into the good microphone.
Corn
A phone in a shirt pocket, at the end of nine metres of cable.
Hilbert
Pinchas says it's on a long lead. I've never seen the lead.
Herman
A shirt pocket is the hard case, Hilbert. Cloth rustle, a mouth at the wrong angle. It's close to the WhatsApp set on the leaderboard, where everyone's error rate gets worse.
Hilbert
Forty minutes to get one clean sentence out of the stairwell. Pinchas says that's the Hebrew's fault. Fair enough, though. A phone doesn't need a cable. I'll tell him. He won't like it.
Corn
That leaves Hannah, who has an app, a microphone and a question.
Herman
Whisperian's local engine is Parakeet, and as far as I know Parakeet is the wrong tool for Hebrew. Its page doesn't mention Hebrew, and it doesn't mention importing your own model either. That's a question for the developer, or a ten-minute test, not something we can answer for her.
Corn
I'd just ask. Developers of small apps tend to answer, and a custom-model option would be a feature worth hearing about.
Herman
What do you think she should do if the answer's no, Corn?
Corn
Use something else for the Hebrew, offline. And since she keeps the transcription step apart from the clean-up step, which is the whole reason Daniel likes the app, she can feed the transcript back in afterwards.
Herman
There are two routes. One is an app that can run the ivrit.ai faster-whisper or ONNX builds locally, which is the accuracy route, around nine percent average error on that leaderboard. The other is the sixty-six million parameter zipformer through the sherpa-onnx runtime, which is the small and light route, around eleven. Both run on her own machine.
Corn
And the cloud options Whisperian offers through API keys?
Herman
OpenAI's transcribe and Deepgram both sit between fourteen and eighteen on the same board, so they'd work, but noticeably worse than the open Hebrew models. For a Hebrew-and-English mix, Daniel's Whisper-Hebrish was built for exactly that, though only measured on his own set. I'd try it before assuming anything.
Corn
So the order is, ask about custom models, then try ivrit.ai, then try Daniel's.
Herman
In that order, and with her own recordings, not a clean test file.
Corn
Hebrew speech recognition got better by feeding a small model the right data, not by waiting for a bigger one. Speech synthesis hasn't flipped that yet, because the best voices are still behind a paywall, and language models are a two-horse race that nobody has measured against the frontier.
Herman
Each modality has a different answer, and that's the useful picture. The open models are close, the closed ones are not extinct, and the evidence for the LLM side is mostly the authors' own tables.
Corn
What stays open for me is whether the next closed model that lands on that Hebrew arena beats the top by a mile or a hundred points.
Herman
That, and whether the next Hebrew model you hear sounds right with the vowels in place. The dots, the vowel marks, are the subject of the next episode, and there's more to them than a letter-to-sound table. The test that counts is your own voice, recorded on your own phone, in your own kitchen, because that's the hard case.
Corn
Thanks to our producer, Hilbert Flumingtop, for keeping the levels sane.
Herman
This has been My Weird Prompts. You can find every episode at my weird prompts dot com.
Corn
See you tomorrow.

This episode was generated with AI assistance. Hosts Herman and Corn are AI personalities. It may contain errors: disclaimer · report an error