# ISSEN

> ISSEN is an AI voice tutor for language learning. Built by Y Combinator Fall 2024 founders Mariano Sorgente and Anton Apostolatos, the app holds free-flowing spoken conversations in 50+ languages, adapts to a learner's level and interests, and lets users tune the tutor's speaking speed, patience, and accent. It targets intermediate-to-advanced self-study learners who want real conversation practice without booking a human teacher, and runs on a B2C subscription across web, iOS, and Android.

- **Founded:** 2024
- **Headquarters:** New York, United States
- **Founders:** Mariano Sorgente (Co-founder & CEO), Anton Apostolatos (Co-founder)
- **Team size:** ~3 (as of mid-2026)
- **Products:** ISSEN AI Voice Tutor, Customizable Tutor Controls, In-context SRS Flashcards, Shadowing & Pronunciation Modes
- **Notable:** Accepted into Y Combinator Fall 2024 (F24) batch, iOS App Store rating around 4.7 stars from ~2,800 ratings, 500,000+ downloads on Google Play

## Products & services

- **ISSEN AI Voice Tutor** — A real-time AI voice tutor that holds free-flowing spoken conversations, switches between structured grammar lessons and casual chat, remembers past sessions, and adapts to the learner's level, interests, and goals across 50+ languages.
- **Customizable Tutor Controls** — Learners tune the tutor's speaking speed, patience, turn-taking, formality (formal/standard/slang), accent, and complexity, and can pick from multiple AI tutor voices.
- **In-context SRS Flashcards** — Spaced-repetition flashcards and saved word lists built automatically from sentences the user actually spoke, plus full session transcripts.
- **Shadowing & Pronunciation Modes** — Shadowing (pronunciation) practice, translation drills, text-chat mode, and background listening across web, iOS, and Android with sync.

## Achievements

- Accepted into Y Combinator Fall 2024 (F24) batch
- iOS App Store rating around 4.7 stars from ~2,800 ratings
- 500,000+ downloads on Google Play
- Product Hunt launch reached #7 product of the day with 200+ upvotes
- Supports 50+ languages with real-time voice conversation

## Latest updates

- **2024-11** — ISSEN publicly launched as part of Y Combinator's Fall 2024 batch.
- **2025-06** — Founders posted a Launch HN detailing the multi-model speech-recognition pipeline behind the tutor.
- **2025-07** — Shipped updated iOS and Android apps with sync, SRS flashcards, and shadowing modes.
- **2026-05** — Team reported at around three people; active company blog with 2026-dated posts.

## Links

- Website: https://issen.com
- LinkedIn: https://www.linkedin.com/company/issenapp
- Twitter/X: https://twitter.com/sorgente711
- GitHub: https://github.com/mariano54

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Profile page: https://yespress.io/issen-yc-f24
Published by YesPress — https://yespress.io
Last updated: 2026-07-30