Launch HN: Issen (YC F24) – Personal AI language tutor
Demo: https://www.loom.com/share/a78e713d46934857a2dc88aed1bb100d?...
We started this company after struggling to find great tools to practice speaking Japanese and French. Having a tutor can be awesome, but there are downsides: they can be expensive (since you pay by the hour), difficult to schedule, and have a high upfront cost (finding a tutor you like often forces you to cycle through a few that you don’t).
We wanted something that would talk with us — realistically, in full conversations — and actually help us improve. So we built it ourselves. The app relies on a custom voice AI pipeline combining STT (speech-to-text), TTS (text-to-speech), LLMs, long term memory, interruptions, turn-taking, etc. Getting speech-to-text to work well for learners was one of the hardest parts — especially with accents, multi-lingual sentences, and noisy environments. We now combine Gemini Flash, Whisper, Scribe, and GPT-4o-transcribe to minimize errors and keep the conversation flowing.
We didn’t want to focus too much on gamification. In our experience, that leads to users performing well in the app, achieving long streaks and so on, without actually getting fluent in the language you're wanting to learn.
With ISSEN you instantly speak and immerse yourself in the language, which, while not easy, is a much more efficient way to learn.
We combine this with a word bank and SRS flashcards for new words learned in the AI voice chats, which allows very rapid improvement in both vocabulary and speaking skills. We also create custom curriculums for each student based on goals, interests, and preferences, and fully customizable settings like speed, turn taking, formality, etc.
App: https://issen.com (works on web, iOS, Android) Pricing: 20 min free trial, $20–29/month (depending on duration and specific geography)
We’d love your feedback — on the tech, the UX, or what you’d wish from a tool like this. Thanks!
281 comments
[ 2.7 ms ] story [ 327 ms ] threadThank you so much for this. Duolingo is literally unbearable because it's so gamified. I'll try it out later. I've seen a few of these apps, can I seamlessly go between my native language and the language I'm trying to learn? If I am trying to learn Hindi, can I ask a question in English in the middle of a conversation?
These kinds of learning apps are destined to become mediocre over time.
The learning metric is so easy to capture, the learning content so easy to produce, yet no one has an individualized loop to make learning work well.
For example, I'd press "Training" on Duolingo, and would get nowhere. Same lessons all of the time. Bread and water.
Btw: if the app is available, I would love to take a look!
How widely have you tested your supported languages on native-speakers and learners?
We've done a lot of testing on Spanish, English, Italian, Japanese, and French, but much less on the others and none at all for some of the niche ones.
The language support is based on the intersection of the languages that have low word errors rates in the transcribers, as well as officially supported by LLM/TTS (like gpt4.1, eleven labs etc).
We've seen the models' quality improve consistently over the last 6 months, in all languages we tested, and now the error rates are getting really low.
Certainly if your product were to mis-teach me important details, and I were to then find out that you had spent less time testing than I had spent learning, I would be quite angry.
I’m going to assume this works better on the App.
However, gamification can only do so much and I'm afraid language learning is a lot like learning to code: many people want to want it but few actually want it. In that case, presenting as a "want it" when you are a "want to want it" is social proof and largely unrelated to whether you are actually learning (as long as the pretense is kept up) — hence the success of Duolingo despite the relatively poor real-world outcomes. In Duolingo's case the streaks are even explicitly considered to be social proof.
Today, it’s not only easier than ever to launch a platform to challenge Duolingo, but its core product—its crowd-sourced human translation service—has been distrupted.
This morning, I found myself thinking about how all those decade-old learning platforms—like Coursera, as reflected in its ever-falling stock price—are being distrupted.
Your product looks awesome and I hope you distrupt all the language learning platforms. Thank you for sharing.
(I had ChatGPT fix my grammatical errors and now this comment doesn't sound like me, sorry.)
And it didn't correct "distrupted" to disrupted?
https://imgur.com/a/m3svUky
That's an image of text. Is it supposed to provide more evidentiary value than the word "Nope" above it would by itself?
I'll bet you I can show you a screenshot where "ChatGPT" says whatever your heart desires.
And mid 2010s view was MOOCs were supposed to disrupt University education!
Add it to the pile.
You can delete your account at any time to fully wipe all your data, but there is no way to delete sessions ATM.
The vocabulary tooling looks neat and well thought out.
Also, we prefer the eleven labs voices, but there is definitely varying quality. I'm guessing later this year or next, the voice to voice models will become good enough, and we will switch over.
For me a key feature will be a family plan; Duolingo is great in that regard.
Even some basic app that can pre-load the prompt doesn't seem to exist?
Now, I tried the web app and chose to learn Greek as a beginner. And while I had better experience with your app than with ChatGPT or Gemini voice modes, I still got lost 5 minutes in because the AI tutor doesn't seem to have a plan for me, nor does it "see" my struggles. For example, after asking me about a hobby, it gives me a long sentence in Greek about how how it is nice to hike in mountains. Being absolute noob I cannot reply to it, nor even repeat it. And I don't even know what it is expected from me at the moment. A human tutor here would probably repeat a part of the sentence with a translation and ask me to repeat, or would explain something. The AI just sits there waiting for me to make a sound, and when I make it, it goes on on a tangental subject of beach vacations. :)
Again, this is still relatively not bad, and I'm going to give it another try.
My thinking is - I can have unstructured conversations with Advanced Voice Mode or in real life here in Sweden. What I'd really appreciate is a guided learning experience taking me up from intermediate/slightly above intermediate to fluent in the most efficient possible way (as opposed to just having us 'ramble' about random topics of my own choosing).
This is available for all proficiencies. It's just much harder to talk for hours in a new language as a beginner. It's usable but requires more effort.
Another thing is that the trial period seems incongruent. To me the structured curriculum is what I really want to _try_. I want to see what the planned lessons are like, how guided they are, etc. But the trial runs out and tries to make me pay right after the unstructured more all-over-the-place feeling introductory conversation, and I'm not prepared to pay at that point since I feel like I haven't gotten to evaluate the main part of the product at all. I would suggest leaving the trial unlocked to maybe the first three structured lessons of the learning plan. Let the user really experience what they'll be paying for.
* curriculum, completely customizable, with grammar, roleplay, topics, speaking speech, transcript, dictionary, corrections, etc
* prompting and AI models all chosen to be a better fit for multilingual, easy to understand, etc.
* the tutor actively tries to teach you, it's not an assistant
* integrated flashcards that go hand in hand with the speaking immersion
I'm not even sure this helps with speaking practice since it's just a test of whether what you said can be transcribed by Whisper, which is not at all a test of correct pronunciation. I just tried it with the most horrid, butchered accent I could muster, and it still worked...if I practiced for months on end like that, I'd end up in a very difficult place as a language learner.
I tried following the modern Japanese track on Memrise and was appalled at how bad it is nowadays.
[0]: https://www.languagetransfer.org/
The feature request I make for all language course makers: please consider Bengali support in the future! It's wild to me that the 7th most spoken language in the world, with a deep culture around literature and poetry [1], gets zero attention from language course makers. I can buy an Assimil course on Breton, spoken by 200k people, and not Bangla, spoken by 284 million.
[1] https://en.wikipedia.org/wiki/Charyapada
The teacher kept switching into an American accent when I was trying to learn French and the responses were getting very slow bitty.
Hopefully this is just an initial load of issues because the concept is great.
Also for the flash cards the audio that says the word starts at the same time with the audio for the example sentence.
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AI: Anh mệt is good if bạn are a man speaking about yourself. You can also say, “Em mệt” if you’re a woman.
this isn't correct. If you are of "older brother" age and are male, you say Anh. Em is for if you are "younger person" (does not matter the gender). Women tend to prefer being called "em" (even if they are older), because women prefer to be identified as younger than their true age... But that doesn't mean you can't call younger men em.
A good tutor would know your age relative to theirs and explain this context.
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It would say english phrases with a vietnamese accent.
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It also would give me really complex vietnamese phrases that I am not ready for. when I prompt for an explaination or translation, it would get off track from the original thing we were learning.
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Way more people in Vietnam (and the globe) speak southern Vietnamese, but the tutors seem to be from north Vietnam.
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The STT also was very forgiving if I pronounced things incorrectly. Or it would confuse english and vietnamese. I would say, "Phai", but it heard "bye"
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I was ready to pull out my credit card, but I can't trust it to teach me the right information. I pay $160/mo for Vietnamese tutoring ($20 per class). This would be way cheaper and I don't have to schedule my classes.
I think this company will end up pivoting into a B2B context before long. Hopefully they will still stick to the mission, but who knows (and I wouldn't fault them if they don't – survival comes first).
If OpenAI puts resources to language learning, they could build a great product. But 3rd party devs relying on someone's tech hasn't proven to be a good strategy.
That is not a problem. Language is messy, you don't need 100% accuracy to learn. The problem is that LLM errors are fundamentally different from human errors, and you won't even know how to recognize them.
Your interlocutors can work around human errors, because they tend to follow the same patterns in same language. But they will freak out with LLM errors.
Trying out your tool, I'd really like to know if the sound is north or southern Vietnamese. I think your tool is southern vietnamese, but idk.. I personally prefer learning southern, but all the AI TTS tools use the north dialect. Ideally, I'd like a 'pure' southern accent and not a hybrid.
For your tool, You might want to get into the way to address people (Anh, em, ba, co, etc). You seem to just use toi (which I hear vietnamese people using with each other too...) but my understanding is the (Anh/Em/Ba/etc) are more 'intimate' whereas toi is more formal/business like?
One idea I haven't tried too much of yet is making flash cards that teach me a sentence structure, but introduce new vocabulary. Learning a diaspora of phrases works for short 2-3 word ones, but when I try to learn more complex sentences, my brain isn't able to draw the patterns as nothing is connected.
For example, trying to learn "bạn tên là gì" and "nhà vệ sinh ở đâu" (from your website) is harder than learning "Bạn tên là gì?", "Bạn nghề là gì?", "Bạn số điện thoại là gì?"
The other huge challenge I have is feeling like I am making progress. I'm definitely getting better, but its pretty disheartening to study for 40+ hours and still can't pronounce words like Can Tho properly, despite knowing how to read and write.
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My email is in my profile. Feel free to reach out to me if you have more updates or want to bounce ideas.
Whisper can transcribe in <100ms. We then wait for the turn detection model, LLM, and tts to trigger a streamed response back to eh client.
The faq wont expand on tap for me on android firefox. Dm me if you need more info.
Looks like a great app and I can't wait to try it for Japanese!
Can the cards be exported to anki?
I tried the Japanese track. I'm a total beginner and the first lesson wasn't helpful at all. The AI asked about maybe mixing up Japanese<>English, but it didn't actually follow through. It either spoke fully in Japanese or fully in English. Maybe this is a standard practice for language lessons? I remember going to the first day of French class in a community college, and the teacher only spoke French, which was extremely overwhelming. Perhaps it's the standard way of teaching? Even if it is, I'm not sure if it works when compressed down to the shorter times I see myself opening the app.
https://x.com/JarrettYe