Simultaneous translation: booth, RSI, or AI — and which tools for your meetings (2026)

"Simultaneous translation" is what everyone types; "simultaneous interpretation" is what the profession calls it. Both name the same thing: speech rendered in another language while it is being spoken — no pauses, no relay. But under that one term hide three very different ways of getting it — the human interpreter in a booth, remote simultaneous interpretation (RSI), and real-time AI translation — and three budgets that have nothing in common.

This guide separates the three, then compares named tools on a verifiable basis: what each vendor's public documentation states, with the source and the date we checked it. We build one of them (InterMIND); we'll say where it fits and where it doesn't.

The three forms of simultaneous translation

1. The interpreter in a booth (the historical standard)

Two interpreters per language pair, a soundproof booth, receivers for the room. This is how institutions and large conferences do it. The quality comes from a professional who understands context, irony, and jargon — and the cost comes from the same place: qualified humans, booked by the day, per language pair, plus equipment. For a weekly working meeting, this setup simply isn't designed to apply.

2. RSI: the human interpreter, remote

Remote-simultaneous-interpretation platforms (Interprefy, KUDO, Boostlingo) deliver human interpreters' audio — sometimes with an AI option alongside — to participants' phones or headsets, on site or in a video call. The setup remains an event: one speaker, an audience, languages fixed in advance, interpreters booked.

3. AI simultaneous translation

No interpreter here: a speech-recognition → machine-translation → speech-synthesis cascade renders the speech in each listener's language within seconds, with nothing to book. This is the only form whose marginal cost fits an ordinary meeting — the category's tipping point. The question then becomes: what does the tool translate, beyond the voice?

The question that actually separates tools

An honest comparison doesn't ask "is the translation good?" — every vendor answers yes. It asks two things:

One speaker, or everyone at once? Event tools optimize one stage → one audience, often one-directional. A working meeting is N people speaking, typing, reading, and replying, each in their own language, both directions, at once. A tool that excels at conferences can be unusable for a four-person standup.

After the audio, what comes back in your language? A meeting isn't just speech: it's the chat, the shared notes, the document dropped mid-session, the record you keep. Most tools translate the spoken moment and stop — the translation evaporates the instant the talking does. Ask any candidate plainly: after the audio, what else comes back in my language?

The tools, on the record

Every fact below comes from the vendor's public documentation, checked August 2026 (links at the end). "Not stated" means we found no claim in the public docs — check with the vendor if the point matters to you.

For events with interpreters (RSI)

• Interprefy — its documentation states 190+ languages and 6,000+ combinations with human interpreters, and 80 languages for its AI translation (audio and captions). (InterMIND vs Interprefy, feature by feature.)
• KUDO — RSI platform with an AI option: the KUDO AI Speech Translator page states translated audio and captions in 60+ languages, alongside human-interpreter delivery.
• Boostlingo — interpreter network: its site states 10K qualified interpreters and 275+ languages on demand, plus AI captions.

For multilingual working meetings

• Wordly — AI-only translation for meetings and events: its documentation states 60+ languages and 3,000+ pairs, with attendees choosing text, audio, or both; its FAQ states translated transcripts and session summaries. Chat, shared-notes, and document translation are not stated in its public documentation (checked August 2026). (InterMIND vs Wordly, feature by feature.)
• DeepL Voice — the product page states live captions in 40+ languages inside Microsoft Teams, Zoom, and Google Meet; voice-to-voice output is listed as "coming soon" (checked August 2026).
• InterMIND — what we build: the whole meeting comes back in each participant's language, both directions. Voice — 23 languages, rendered in the speaker's own voice, live (how the cascade works); chat and shared notes — translated live, per viewer, in the same 23 languages; documents dropped in-meeting (PDF, DOCX, PPTX, XLSX) — returned in 30 languages with formatting intact (the honest per-surface count); the post-meeting summary — generated in your language, on EU-hosted models with zero retention of meeting data (the GDPR audit). Quality is published, not claimed: the production cascade is scored monthly against FLORES-200, full per-pair distribution, at /benchmark.

Inside the platforms you already use

• Zoom — translated captions in 36 languages (Business Plus/Enterprise or a paid add-on); a Voice translator that renders translated audio (AI Companion, US-cluster accounts, desktop app 7.0+); and audio channels for up to 20 human interpreters you source yourself. (Full breakdown.)
• Microsoft Teams — translated captions in 31 languages (Teams Premium or Copilot); an Interpreter agent that translates speech into speech, optionally simulating the speaker's voice (Copilot license); channels for 16 language pairs of human interpreters. (Full breakdown.)
• Google Meet — translated captions (Workspace Business Standard and above) and Gemini speech translation "in a voice like yours" (qualifying plans). (Full breakdown.)

The table: how much of the meeting comes back in your language?

Every cell is what the vendor's own public documentation states, checked August 2026.

Two honest notes on our own row: the counts differ per surface (voice/chat/notes 23, documents 30, website 17 languages — the breakdown and why); and voice quality is checked on /benchmark, not in this table.

The decision shortcut

• Conference with an audience + human interpreters required → Interprefy, KUDO, Boostlingo.
• Working meeting, several people, both directions, AI → Wordly, DeepL Voice, InterMIND — and here, test three things specifically: the rendered voice (generic or the speaker's own), coverage beyond the audio (chat, notes, documents, the record), and quality that is published rather than claimed.
• Captions are enough → your existing Zoom/Teams/Meet, with the license gates in the table.

FAQ

What is the best simultaneous translation software for meetings? Depends on the setup. For an event with an audience and interpreters: Interprefy (80 AI languages, 190+ with interpreters), KUDO (60+), or Boostlingo. For a working meeting where everyone speaks, types, and reads in their own language, both directions: Wordly states 60+ languages as audio and text; InterMIND translates voice (23 languages, in the speaker's own voice), chat and notes (23), and documents (30) per participant. For captions only: Zoom (36 languages), Teams (31), or Meet, depending on your plan.

What is the difference between simultaneous translation and simultaneous interpretation? In practice, none: "simultaneous interpretation" is the professional term for real-time spoken rendering, "simultaneous translation" the everyday one. Strictly, translation concerns text and interpretation speech — we unpacked the distinction and the types of interpretation here.

Can Zoom, Teams, or Google Meet do simultaneous translation? Yes, with plan gates. Zoom: translated captions in 36 languages (Business Plus/Enterprise or a paid add-on) and translated audio via the Voice translator (AI Companion, US cluster). Teams: captions in 31 languages (Premium/Copilot) and the speech-to-speech Interpreter agent (Copilot license). Meet: translated captions (Business Standard+) and Gemini speech translation on qualifying plans. Per-platform detail: Zoom, Teams, Meet.

Can AI simultaneous translation keep the speaker's voice? Most AI tools render every speaker as the same synthetic narrator. A few state output close to the original voice: Teams' Interpreter agent can "simulate" the speaker's voice, Google Meet states "a voice like yours," and InterMIND renders the translation in the speaker's own voice via zero-shot synthesis, in 23 languages — how that works.

How does AI simultaneous translation work? A three-stage cascade: speech recognition transcribes the speech, machine translation converts it, speech synthesis renders it — continuously, a few seconds behind. Each stage fails in its own ways; we documented the production cascade stage by stage here, and how to evaluate any tool in this category here.

See it for yourself

For the multilingual working meeting, the fastest test — for any tool, ours included — is to put your own meeting through it: talk, then check whether the chat, the notes, and the document came back in your language too.

• Try the live demo — InterMIND's production voice cascade, on your own audio, in any of 23 languages.
• Read the benchmark — monthly FLORES-200 scores, full per-pair distribution, no cherry-picking.
• How to evaluate a real-time meeting translator — the vendor-neutral foundation behind this guide.

Sources: Interprefy — AI translation languages, Interprefy — platform, KUDO — AI Speech Translator, Boostlingo, Wordly — translator languages, Wordly — FAQ, DeepL — Voice, Zoom — viewing captions in another language, Zoom — Voice translator, Zoom — Language Interpretation, Microsoft — live captions in Teams meetings, Microsoft — Interpreter in Teams, Microsoft — language interpretation in Teams, Google Meet — translated captions, Google Meet — Speech Translation, checked August 2026. Vendors expand plans and language lists over time; check their pages for the current state. InterMIND facts: per-surface language breakdown, live benchmark.