Live events increasingly serve audiences that speak more than one language. Whether you are running a conference, a product launch, or a hybrid forum connecting rooms across different countries, the expectation of accurate, real-time translated captions is growing fast.

For AV teams, the challenge is practical: how do you take a live speech-to-text feed and reliably convert it into readable captions across multiple languages at once, routed to the right screens or streams, without the event grinding to a halt?

This article looks at five platforms built for exactly that. The focus is live caption machine translation, which means ASR-generated captions translated in real time and delivered as readable text to live audiences. This is distinct from human interpretation or audio dubbing. We are talking about text output only.

For broader context on captioning delivery methods, see our overview of live captioning tools.

Quick Comparison: Live Caption Machine Translation Platforms

Pricing reflects publicly available information at time of publication.¹² Contact vendors directly for event-specific quotes.

1. SyncWords

SyncWords is a broadcast and live event captioning platform that delivers real-time translated captions across 100-plus languages³ with low latency. It captures live speech, converts it to text via ASR, and translates that text into target languages simultaneously, outputting captions to HLS streams, OTT platforms, and live event screens in parallel.³

The platform is built around broadcast-grade delivery. Rather than relying on attendees to access captions through a personal device, SyncWords pushes translated caption output directly to production channels, which makes it a natural fit for events where caption delivery is integrated into the wider video and AV infrastructure.³ Multiple language outputs can run simultaneously from the same live feed, with each language routed to its corresponding destination without manual intervention during the session.³

For operators managing complex live productions, SyncWords supports integration with over 100 virtual event platforms and streaming workflows, and its output destinations include HLS, OTT, browser-based players, and on-site display screens.³ The platform handles the translation layer automatically, so AV teams do not need to manage separate translation tools alongside their existing caption setup.

SyncWords also supports simu-live playback, allowing pre-recorded video to be paired with perfectly timed captions and translations to simulate a live experience on any virtual event platform.³ Post-event analytics covering attendee numbers, languages activated, and access patterns are available for operators who want to track engagement across multilingual sessions.³

Best for: Events with strong broadcast or streaming requirements where simultaneous translated caption delivery across screens and digital channels is a production priority.

2. Wordly

Wordly provides AI-powered translated captions accessible via attendee devices, with no specialist hardware required on-site.⁴ Attendees pick their preferred language from a mobile or desktop interface, and all supported languages are available within the same session at the same time.⁴

The platform supports over 60 languages for translated caption output.⁴ Translation runs automatically from the live speech feed, with no manual switching required between languages during the event. Each attendee selects their preferred language independently, so a single session can serve audiences across multiple language groups simultaneously without any additional configuration from the operator.⁴

Output reaches attendees through browser-based links on personal devices, which keeps the setup lightweight for AV teams. There is no dedicated hardware to install and no app that attendees are required to download, which lowers friction at the point of access.⁴ For events running across both physical and remote audiences, this device-agnostic approach means the same caption feed serves in-room and online participants through the same interface.

Wordly is well known for its integrations with Microsoft Teams and Zoom, which makes it a practical option if your event runs fully or partially through those platforms.⁴ For in-person and hybrid events, it works equally well as a standalone browser-based tool.

Custom glossaries help maintain consistency for specialist terminology, and ISO 27001 and SOC 2 Type II certifications give enterprise event teams confidence around data handling.⁴ Post-event transcripts and summaries in multiple languages add further value for organisers distributing content after the session.⁴

Wordly charges per hour of usage at a flat rate regardless of how many languages are active, which simplifies cost forecasting for multi-day or multi-track events.⁴

Best for: Hybrid or in-person events where attendee-side language access via personal devices is the primary goal and operational simplicity matters.

3. Verbit

Verbit combines ASR with a layer of AI post-processing to improve caption accuracy in live settings.⁵ The platform is used across higher education, legal, and corporate event environments, and supports integration with a range of event platforms and content management systems via API.⁵

Where Verbit differentiates itself is in accuracy tuning. Its models are trained on domain-specific vocabulary, which can reduce errors in technical or formal contexts where generic ASR engines tend to struggle. Translation output is available for select language combinations, making it a reasonable option where caption accuracy in the source language is as important as the translated output.⁵

Best for: Events in regulated or technical sectors where source-language caption accuracy is a priority alongside translated output.

4. Ava

Ava is an accessibility-focused captioning platform that uses AI to generate real-time captions, accessible via browser and mobile app.⁶ It is not a CART service and does not use human captioners. Translated caption output is available for select languages, and the interface is designed with readability in mind, which benefits audiences who may not be used to reading live captions.⁶

Ava supports speaker identification, so audience members can follow who is speaking even in multi-speaker formats. For smaller or mid-scale events where ease of attendee access is a priority and the language set is limited, it is a straightforward option to deploy.⁶

Best for: Smaller events where simple attendee access and caption readability are the primary requirements, and the required language set is covered by Ava's translation output.

5. Line 21

Line 21 is designed around a clear channel architecture where each language in a live event runs as its own independent track, with its own source and its own output destination.² Multiple channels run in parallel throughout the event, and there is no fixed limit on how many language outputs can be active at once.²

A key distinction from other platforms in this list is that Line 21 does not constrain translation by pre-defined language pairs.² Any supported input language can be translated to any supported output language in text.² The platform currently supports 99 languages for AI translation output,² drawing on engines including DeepL, Azure, Google, and OpenAI.² Teams can select engines per language based on preference or accuracy requirements, or let the platform handle engine selection automatically.²

Input sources can be mixed within a single project.² Human captioners, ASR engines, and translation engines can all feed into different channels simultaneously.² A multi-language ASR input can detect the language being spoken on stage and generate captions across multiple output tracks without requiring the operator to switch manually between sessions.²

Output destinations are broad: browser-based audience links, display overlays, RTMP streams, HLS video players, CEA 608/708 broadcast caption tracks, and text API endpoints can all receive translated caption output from the same live production setup.² An AI Proofreader runs in real time across all active channels to catch transcription and translation errors before they reach the audience.²

For events where terminology matters, such as pharmaceutical conferences, legal forums, or financial summits, custom dictionaries allow teams to pre-load specific vocabulary and ensure consistent handling across all language tracks.²

Best for: Live events that need multiple simultaneous translated caption outputs delivered across a range of destinations, with full visibility over engine selection and the flexibility to translate between any supported languages without fixed constraints.

Volume discounts: Line 21 offers volume pricing for organisations running frequent or large-scale events. Contact the team directly to discuss rates based on your event schedule and language requirements.²

Choosing the Right Live Caption Machine Translation Platform

Choosing the right platform comes down to a few key factors: the scale of your event, how attendees will access captions, the languages you need to support, and how captions need to be delivered.

If your event has a heavy broadcast or streaming component, SyncWords is worth considering for its multi-destination output and broad language coverage.³ Wordly works well for hybrid and in-person events where attendees need to access translated captions on their own devices with minimal setup.⁴ Verbit is a good fit for technical or regulated sectors where getting the source-language transcription right is just as important as the translated output.⁵ Ava suits smaller events with modest language requirements, particularly where caption readability and simplicity of access are the main priorities.⁶

For events where flexible language routing and broad delivery options matter, Line 21 is worth a close look.² Its channel-based architecture means each language runs as an independent track with its own input and output, giving teams clear visibility and control without a complicated setup. There are no fixed language-pair constraints, so you can translate between any supported languages without being tied to pre-set combinations.² With delivery options spanning browser links, overlays, RTMP, HLS, CEA 608/708, and API endpoints, it covers most production scenarios from a single, straightforward setup.²

If you are weighing up the options for an upcoming event, the Line 21 team is happy to walk through your setup, language requirements, and delivery destinations. The platform is designed to be straightforward to use, with a clear dashboard and full visibility over engine selection, so you are not handing control to a black box.²