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English to Spanish speech translation API

Stream English (English) speech and get Spanish (Español) back in real time. One WebSocket, ISO codes en to es, and ultra-low latency for voice agents and live apps.

Trusted by

Production-ready English to Spanish translation API

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

English (Indo-European > Germanic > West Germanic) and Spanish (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.

Soniox preserves formatting in the translated transcript, including names, numbers, addresses, IDs, and domain-specific terms.

A breakthrough in real-time English to Spanish translation

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Translate before the sentence ends

Spanish meaning lands as English is spoken, not after the caption catches up.

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Directional en to es streaming

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

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High quality Spanish output

Same model across every language, including historically underserved ones.

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Native-speaker English STT accuracy

Accurate Spanish translation starts with accurate English recognition across accents and language switching.

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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": "en",
    "target_language": "es"
  }
}

English and Spanish through a single stream

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

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

Live English to Spanish: written and spoken

English to Spanish speech-to-text

micLive English speecharrow_right_altsubjectSpanish text

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

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

English to Spanish speech-to-speech

micLive English speecharrow_right_altvolume_upSpoken Spanish

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

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

Live English to Spanish translation in action

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

voice_selection
English speaker says: “Oh, FYI, the client moved the demo to 9:30, so we’re not totally sprinting.”
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Translated into Spanish in real time.

One-way translation

Translate live English into Spanish. Everyone in the conversation sees the same translated stream.

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

voice_selection
English speaker talks in English.
hearing
Spanish speaker hears Spanish.
voice_selection
Spanish speaker replies in Spanish.
hearing
English speaker hears English.

Two-way translation

Translate between English and Spanish 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 English at 6.5% word error rate and Spanish at 5.3% 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.

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About English and Spanish

English has roughly 1,500,000,000 speakers across United States, United Kingdom, Canada, and Australia. Spanish has roughly 500,000,000 speakers across Spain, Mexico, Colombia, and Argentina.

English is the most widely spoken language in the world when including both native and non-native speakers.

Spanish is the second most spoken language in the world by native speakers, after Mandarin Chinese.

Soniox makes English to Spanish usable in real-time translation across every supported pair.

Translate English to any language

From English to Spanish, or English to any of 60+ supported languages. All real-time.

AfrikaansAlbanianArabicAzerbaijaniBasqueBelarusianBengaliBosnianBulgarianCatalanChineseCroatianCzechDanishDutchEstonianFinnishFrenchGalicianGermanGreekGujaratiHebrewHindiHungarianIndonesianItalianJapaneseKannadaKazakhKoreanLatvianLithuanianMacedonianMalayMalayalamMarathiNorwegianPersianPolishPortuguesePunjabiRomanianRussianSerbianSlovakSlovenianSpanishSwahiliSwedishTagalogTamilTeluguThaiTurkishUkrainianUrduVietnameseWelsh

Related translation pages

swap_horizTranslate Spanish to Englisharrow_right_alttranslateEnglish speech translationarrow_right_alttranslateSpanish speech translationarrow_right_altarrow_right_altEnglish to Dutcharrow_right_altarrow_right_altEnglish to Germanarrow_right_altarrow_right_altEnglish to Afrikaansarrow_right_alt

Frequently asked questions

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

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