Cuckoo teaches an AI your jargon before it interprets your call
The YC W25 startup drops a live interpreter into your meetings across 20+ languages - and learns your pitch decks and API docs first, so the technical details survive the trip between languages.
Matt runs solutions engineering at PagerDuty. His hardest calls are not the ones full of stack traces and incident timelines. They are the ones where a customer in Seoul or Tokyo asks a sharp technical question, and Matt watches the answer lose a little of itself on the way across the language line. "Nuances and details can get lost between languages," he has said, "especially during technical conversations." That gap - the space between what you meant and what the other side heard - is the entire reason Cuckoo exists.
Cuckoo is a real-time AI interpreter built for business. You invite it into a Zoom call, or let it listen to a room, and it translates the conversation live across more than twenty languages. That part is not new; captions and machine translation have existed for years. What Cuckoo adds is preparation. Before the meeting, you hand it your pitch deck, your API documentation, your product glossary. It reads them. So when someone says a word that means one thing in general English and something very specific inside your company, Cuckoo already knows which one you meant.
The problem hiding inside every global deal
Language is the last unpriced tax on going global. Companies budget for travel, for local hires, for legal. They rarely budget for the slow leak of meaning that happens when a mistranslated technical detail costs a deal, delays a renewal, or turns a support ticket into three. The usual fixes are blunt. Human interpreters are excellent and expensive, and they do not scale to every sales call and every customer troubleshooting session. Generic machine translation scales infinitely but flattens nuance - it does not know that in your world, a "runner" is a job type and not a person who jogs.
Cuckoo's bet is that the sweet spot is an interpreter that behaves like a human colleague who did the reading. It shows up already fluent in your product. And it keeps the receipts: the more meetings it sits through with a given team or customer, the better it gets at their accents, their shorthand, their recurring terms.
How it actually works
The mechanics are refreshingly plain, which is usually a sign that a lot of engineering went into making them plain.
Invite
Add Cuckoo to an online meeting, or let it capture audio from an in-person conversation.
Feed it context
Upload decks, API docs, manuals, and glossaries so it learns your domain terminology.
Speak
Everyone talks in their own language; Cuckoo interprets live in each participant's preferred one.
Compound
Accuracy climbs across repeated meetings as it remembers context and speech patterns.
That last step is the quiet moat. Most translation tools are as good on day one as they will ever be. Cuckoo is designed to be a little sharper on your tenth call with a customer than it was on your first. The company describes the result as something close to having an in-house interpreter fluent in more than twenty languages - the kind of hire almost no company could justify, recreated in software.
Illustrative How the approaches stack up on domain-specific technical accuracy. Human interpreters lead on nuance; Cuckoo aims to combine that context-awareness with the scale of software. Positions are approximate.
Who is already using it
For a company this young, the customer list is the headline. Within roughly six months of launch, Cuckoo had signed global technology firms and companies pushing into Asian markets - the exact places where the language tax bites hardest.
Named users and adopters, alongside clients in healthcare, manufacturing, and retail. The common thread is technical conversations that cannot afford to be approximate.
The people behind it
Cuckoo was founded in 2024 by Yong Hee Lee and Gunwoo Kim, who met in 2015 through a student club at KAIST that organized an annual international conference for undergraduates. Lee, the CEO, came up through go-to-market roles as an early sales hire at Korean startups. Kim, the CTO, had earlier built a ride-hailing app in South Korea that reached a million users in nine months. One founder knows how to sell across borders; the other knows how to ship at speed. It is a tidy division of labor for a company whose whole product is about crossing borders.
Business, money, and the market it lives in
The model is straightforward B2B SaaS. Cuckoo offers a free first conversation - "your first conversation is on us" - then converts teams into paying subscribers for ongoing interpretation. In 2025 the company went through Y Combinator's Winter batch and raised a $1.8 million seed round led by YC, with Smilegate Investment, Mashup Ventures, Base Ventures, Schmidt, and BonAngels Venture Partners joining. The stated plan for the money is unglamorous and sensible: build the product, expand globally, and keep improving the interpretation engine.
In market terms, Cuckoo sits between three worlds it is trying not to be. It is faster and cheaper than a human interpretation agency, more context-aware than generic machine translation like Google Translate or Microsoft Translator, and more purpose-built than the translation and captioning features bolted onto meeting tools. The wager is that global enterprises will pay for the middle path: interpretation that scales like software but reads like it did its homework.