Get the AppBuild with API

Japanese to French speech translation API

Stream Japanese (日本語) speech and get French (Français) back in real time. One WebSocket, ISO codes ja to fr, and ultra-low latency for voice agents and live apps.

Trusted by

Production-ready Japanese to French translation API

Real Japanese speech includes accents, regional dialects, code switching, and domain-specific vocabulary. Soniox recognizes it in a single model and streams French while the speaker is still talking.

Japanese (Japonic) and French (Indo-European > Romance > Western Romance) come from different language families, so word order and morphology differ. Soniox reorders meaning in-stream instead of word by word.

Japanese is written in CJK and French in Latin, so Soniox emits correctly scripted French text.

A breakthrough in real-time Japanese to French translation

check

Translate before the sentence ends

French meaning lands as Japanese is spoken, not after the caption catches up.

check

Directional ja to fr streaming

Set the source and target codes once. Both arrive in a single labeled token stream.

check

High quality French output

Same model across every language, including historically underserved ones.

check

Native-speaker Japanese STT accuracy

Accurate French translation starts with accurate Japanese recognition across accents and language switching.

check

Names, numbers, and domain terms

Preserved across the pair, including phone numbers, emails, and IDs.

config.json
{
  "model": "stt-rt-v4",
  "translation": {
    "type": "one_way",
    "source_language": "ja",
    "target_language": "fr"
  }
}

Japanese and French through a single stream

Japanese to French translation is built on top of Soniox Speech-to-Text API. Every spoken word is transcribed, and French translation streams mid-sentence in the same labeled token stream.

Turn it on by adding a translation block with source_language: "ja" and target_language: "fr". It runs on the same WebSocket and the same model, with no extra round trip.

Live Japanese to French: written and spoken

Japanese to French speech-to-text

micLive Japanese speecharrow_right_altsubjectFrench text

Translate live Japanese into written French with the Soniox STT API. Soniox streams the Japanese transcript and the French translation as speech happens.

Use it for French captions, subtitles, meeting translation, agent assist, and multilingual transcription.

Japanese to French speech-to-speech

micLive Japanese speecharrow_right_altvolume_upSpoken French

Build full spoken Japanese to French translation by combining Soniox STT and Soniox TTS. Soniox recognizes Japanese, translates it, and speaks French with low latency.

Use it for live interpreters, bilingual voice agents, travel assistants, and customer support.

Live Japanese to French translation in action

Stream Japanese to French one-way to push all speech into French, or two-way to keep a bilingual conversation flowing between the two languages.

voice_selection
Japanese speaker says: “Slackで9:30にrescheduleって送っておくね。”
translate
Translated into French in real time.

One-way translation

Translate live Japanese into French. Everyone in the conversation sees the same translated stream.

Ideal for live captions, multilingual meetings, broadcasts, lectures, and customer calls.

voice_selection
Japanese speaker talks in Japanese.
hearing
French speaker hears French.
voice_selection
French speaker replies in French.
hearing
Japanese speaker hears Japanese.

Two-way translation

Translate between Japanese and French for live bilingual conversation. Each side speaks naturally and hears the other in their own language.

Soniox supports real-time two-way translation between any two of 60+ supported languages.

Accurate on both ends of the pair

Soniox transcribes Japanese at 8.7% word error rate and French at 5.7% word error rate. Accurate recognition on both sides is what makes the translation reliable.

speech_to_text

Speech-to-Text

Native-speaker accuracy across 60+ languages, with support for multilingual speech, alphanumerics, speaker diarization, context.

translate

Translation

Real-time streaming translation across 3,600 language pairs, built for high quality and low delay across all supported languages.

text_to_speech

Text-to-speech

High-fidelity speech generation in 60+ languages, built for names, alphanumerics, language switching, and ultra-low-latency streaming.

Together, they create a complete real-time low-latency speech AI platform.

quiz
About Japanese and French

Japanese has roughly 125,000,000 speakers across Japan. French has roughly 280,000,000 speakers across France, Democratic Republic of Congo, Canada, and Madagascar.

Japanese uses three writing systems simultaneously: kanji (Chinese characters), hiragana, and katakana.

French was the international language of diplomacy and high culture from the 17th to the mid-20th century.

Soniox makes Japanese to French usable in real-time translation across every supported pair.

Translate Japanese to any language

From Japanese to French, or Japanese to any of 60+ supported languages. All real-time.

AfrikaansAlbanianArabicAzerbaijaniBasqueBelarusianBengaliBosnianBulgarianCatalanChineseCroatianCzechDanishDutchEnglishEstonianFinnishFrenchGalicianGermanGreekGujaratiHebrewHindiHungarianIndonesianItalianKannadaKazakhKoreanLatvianLithuanianMacedonianMalayMalayalamMarathiNorwegianPersianPolishPortuguesePunjabiRomanianRussianSerbianSlovakSlovenianSpanishSwahiliSwedishTagalogTamilTeluguThaiTurkishUkrainianUrduVietnameseWelsh

Related translation pages

swap_horizTranslate French to Japanesearrow_right_alttranslateJapanese speech translationarrow_right_alttranslateFrench speech translationarrow_right_alt

Frequently asked questions

How do I translate Japanese to French with the API?arrow_downward
Add a translation block to your real-time request with source_language "ja" and target_language "fr". Soniox transcribes Japanese and streams the French translation over the same WebSocket.
Is Japanese to French translation real-time?arrow_downward
Yes. Soniox streams French while Japanese is still being spoken, so meaning arrives mid-sentence instead of after the sentence ends.
What about translating French to Japanese?arrow_downward
That direction is supported too. See the French to Japanese page, or use two-way translation to run both directions in one session.
Does Soniox handle CJK to Latin output?arrow_downward
Yes. Soniox outputs correctly scripted French text in Latin directly in the token stream.
Does Soniox handle Japanese dialects and accents?arrow_downward
Yes. Soniox handles Japanese dialects like Kanto, Kansai, and Tohoku in a single model, so French translation stays accurate across regions.
Which other providers support Japanese to French?arrow_downward
Based on their public docs, OpenAI, Google, Azure, and Speechmatics list both Japanese and French for real-time translation. Soniox is the only one that also supports two-way live translation across 60+ languages.
How fast is Japanese to French translation?arrow_downward
Soniox streams French as Japanese is being spoken, with ultra-low latency. Translation arrives before the sentence ends.

Ready to get started?

Create an account instantly, or contact us to design a custom package for your business.

Build with API arrow_right_alt

Documentation

Get up and running in minutes and spend your time building the product, not wrestling with the API.

Explore docs

See what you’ll pay

Pay only for what you use with our flexible pricing. Built to scale with you.

Pricing details