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Launch HN: Issen (YC F24) – Personal AI language tutor

313 points mariano54 | 7 comments | 26 Jun 25 14:32 UTC | HN request time: 0.433s | source | bottom

Hey HN, we're Mariano and Anton from ISSEN (https://issen.com), a foreign language voice tutor app that adapts to your interests, goals, and needs.

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!

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iandanforth ◴[26 Jun 25 16:13 UTC] No.44388789[source]▶
Alright, having tried this with Japanese I can say it's frustrating. As a near complete beginner the tutor kept speaking in Japanese even when I said "sorry I don't understand" repeatedly and then when I asked it to start in English and then gradually transition to Japanese it lasted all of one sentence in English before switching back. I can totally see how this would be useful conversation practice if you've progressed that far, but I'd love to have something for even earlier beginners. Also since many of the models you use are natively multi modal this could readily integrate visual media for discussion and grounding.

Also, for the transcription it would be great to get pure romanji to start with!

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antonaf ◴[26 Jun 25 16:24 UTC] No.44388888[source]▶
Yes, I can understand and empathize with your experience. Quite honestly our current focus is more for B1+ students. That 0 -> 1 / bootstrapping of the language is much better served by traditional material that is less talking / listening-heavy.
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1. iandanforth ◴[26 Jun 25 18:45 UTC] No.44390141[source]▶
This is demonstrably false. Natural language acquisition is almost entirely listening and talking. The fastest and most consistently effective way to learn a language is immersion. The reason traditional material doesn't attempt immersive techniques is because it is much much easier to print a static book than it is to produce interactive and adaptive content.

The promise and potential of LLM based language learning apps is that you can cross that gap to full immersion in a way that has never been possible before.

Please be more ambitious.

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2. npinsker ◴[26 Jun 25 19:14 UTC] No.44390392[source]▶
Your comment sparked an idea of a conversation with an agent where at any time you could ask, “what’s this word?” and it would respond with an image explaining it. I’m surprised there don't seem to be voice apps that integrate any visual content.
3. thaumasiotes ◴[26 Jun 25 21:14 UTC] No.44391453[source]▶
> The reason traditional material doesn't attempt immersive techniques is because it is much much easier to print a static book than it is to produce interactive and adaptive content.

No, that's not correct.

First off, you can provide immersion with static books. A common favorite here on HN is Lingua Latina per se illustrata ["the Latin tongue explained by itself"].

Second off, there are two reasons that traditional material doesn't do this. The biggest one is student demand; people are afraid of immersion. The second is that the traditional approach is faster. It's lower quality, and it tops out well below the level you hope to reach, but it's faster, not slower. It takes babies a year to learn to say they're hungry. It takes an elementary school class studying a foreign language less than a day.

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4. ◴[26 Jun 25 23:19 UTC] No.44392396[source]▶
5. glandium ◴[27 Jun 25 03:36 UTC] No.44393488[source]▶
> Natural language acquisition is almost entirely listening and talking.

And it's bootstrapped by 1+ year of listening before being even able to speak, let alone talk intelligibly. That's not really an appealing process to anyone beyond that age.

6. jamager ◴[27 Jun 25 09:28 UTC] No.44395263[source]▶
> Natural language acquisition is almost entirely listening and talking

Listening and reading. Talking goes last. See Steve Kaufmann, for example

7. ookdatnog ◴[27 Jun 25 13:01 UTC] No.44396469[source]▶
Learning primarily through listening and talking only works if you have an enormous amount of high quality data, ie, the situation you're in as a baby when you're surrounded by native speakers who are producing speech for hours every day.

If you are an adult and want to spend, say, a couple of hours each week learning a language from scratch, especially without constant access to a native speaker, your initial progress will be much faster if you study grammar and vocabulary in a traditional class from a text book, than if you just try to pick up patterns from listening to the TV or something.

I can't source my claim. I attended a public lecture years ago from a researcher about exactly this misconception.