Kotoba

Frontier speech AI · Tokyo & SF

Ever worked with someone who doesn’t speak your language natively?

Kotoba ships AI speech translation and more

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Kotoba

Products

We ship our own frontier speech models

For teams

Meeting tool

Zoom, Google Meet, etc.

For everyone

Mobile App

Live translator in your pocket

iOS · Android

For builders

Koto models

Frontier ASR, TTS, and STS translation

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Kotoba

Some of the team

Research to app

Yuta Sasaki

Founding ML Engineer

Qian Cheng

Machine Learning Engineer

Jaeeon Park

NLP Researcher

Justin Garcia

Full Stack Application Engineer

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Kotoba

How we train · Qian Cheng

How we train Koto:

1

Data

Human speech audio

2

Pretrain

Model learns speech patterns

3

Fine-tune

Paired examples teach translation

4

Align & evaluate

Check accuracy and latency

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Kotoba

How inference works · Yuta Sasaki

Conventional speech translation

Step 1

Audio processing

Clean up the input audio

→

Step 2

Speech recognition

Speech → text

→

Step 3

Text translation

Text → text

→

Step 4

Speech synthesis

Text → speech

Four models in a chain: latency adds up and each module’s errors propagate downstream

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Kotoba

How inference works · Yuta Sasaki

How Koto works: full-duplex

Input

Audio processing

Listens while the speaker is still talking

→

One model

Output

Translated speech

Speaks while it is still listening

Low latency and high accuracy

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Kotoba

Building products • Justin Garcia

Customer feedback to shipping

Gather feedback from customers

Prioritize

Build, test and ship

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Kotoba

Working at Kotoba · Jaeeon Park

Real conversations shape our research

Look beyond benchmark scores

Translation quality, latency, and conversational flow.

Discover failure modes through dogfooding

Use the product ourselves to see where conversations break down.

Turn observations into testable hypotheses

Design controlled experiments and use the evidence to choose the next step.

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Kotoba

Careers

We’re hiring

AI Researcher San Francisco

Speech Edge AI Researcher Tokyo & SF

Full-Stack Engineer Tokyo

Infrastructure Engineer Tokyo & SF

Technical Account Manager Tokyo & SF

More GTM · Comms · Partnerships

site.kotoba.tech/company#careers Talk to us after ⟶

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