Downloads require your action
LangCompass does not request a model download when you open a lesson. It asks the browser to create a tool only after you explicitly choose Download & generate.
On-device AI guide
Before you use Learning tools
LangCompass can ask AI built into a supported browser to translate, explain, create examples, summarize lessons, and check a sentence. The work happens on your device, but it can require browser-managed downloads, storage, memory, and processing power.
Learning tools are optional. The curriculum explorer and every curated lesson continue to work without them.
The short version
How it works
Chrome chooses and runs the model
LangCompass does not host an AI model or send a prompt to an AI server. The browser creates the appropriate local session for the selected task.
Generated content stays separate
AI output is labelled, stored separately from the curated lesson, and never silently replaces lesson content or your original sentence.
History is local site data
Recent and saved results belong to this browser profile and device. They do not sync to another profile, browser, or computer.
What stays private
The selected lesson passage, a sentence you write, and the generated response are processed through the browser's on-device API. LangCompass has no AI backend, account, API key, or cloud fallback.
Chrome states that after the required browser model has been downloaded, model input is processed locally and is not sent to Google or another third party. Edge makes a similar statement for its built-in models.
If recent history is enabled, LangCompass stores the source and result in this site's IndexedDB storage. Use Results to delete individual or filtered groups. Clearing LangCompass site data removes those results, but it does not necessarily remove browser-managed AI models.
Storage and performance
Downloads and impact on your machine
There is no single honest download-size number. Translation uses language-pair packs, while explanation, examples, summaries, and sentence checking can use a foundation model plus task-specific resources. Exact sizes can change with browser and model updates.
Chrome requires at least 22 GB of free space before it will make foundation-model tools available. This is an eligibility and safety requirement—not a claim that LangCompass downloads 22 GB. Chrome says the actual model is significantly smaller and exposes its current size in chrome://on-device-internals.
Chrome manages downloads and updates in the background. A model update can involve downloading a complete replacement. If free storage later falls below 10 GB, Chrome may remove the model and download it again when requirements are met.
While generating, the browser uses local CPU or GPU capacity and memory. On some machines this can temporarily increase battery use, heat, fan activity, or response time. You can cancel generation, close the panel, or ignore Learning tools completely.
Free disk space
How to remove downloaded models
Model removal is controlled by Chrome, not by LangCompass. The browser can share one foundation model across explanation, examples, summaries, sentence checking, other websites, and Chrome features. A per-tool delete button would therefore suggest separation that does not exist.
In desktop Chrome:
- Open the Chrome menu and select Settings.
- Open System.
- Turn off On-device AI.
Chrome deletes its downloaded generative AI models and frees their disk space. If you turn the setting on again, Chrome can download the models again when an eligible feature needs them.
You can paste chrome://settings/system into Chrome's address bar. Websites cannot open protected chrome:// pages for you.
Translation is different. It uses language-pair packs rather than the shared generative foundation model. Chrome does not currently expose a website API for deleting an individual translation pack, so LangCompass cannot offer an honest per-language removal control.
Removing browser models does not delete your recent or saved LangCompass results. Those are separate site data and remain under Results until their retention period expires or you delete them.
Full toolset
Device requirements
Translation has lighter, language-pack-specific requirements. The complete LangCompass toolset also uses browser foundation-model APIs, for which Chrome currently documents these requirements:
- Windows 10 or 11, macOS 13 or newer, Linux, or a supported Chromebook Plus device
- At least 22 GB free on the volume containing the Chrome profile
- Either more than 4 GB GPU memory, or at least 16 GB system memory and four CPU cores
- An unmetered connection for the initial model or language-pack downloads
Meeting these numbers does not guarantee every API or language pair. Browser policy, model rollout, profile eligibility, and exact task options can still affect availability. LangCompass checks each tool separately.
Compatibility
Which browser should you use?
| Browser | Current guidance | What to expect |
|---|---|---|
| Desktop Chrome | Use the latest version; Chrome 149+ is recommended for the complete multilingual experience. | LangCompass's primary supported and tested browser. Translator and Summarizer shipped in Chrome 138; the web Prompt API shipped in Chrome 148. |
| Microsoft Edge | Edge 148+ exposes matching Translator and Prompt APIs, but complete LangCompass coverage is not yet validated. | Best-effort support. Individual tools may be ready, unavailable, or experimental depending on Edge version, channel, device, and policy. |
| Mobile, Firefox, Safari, and others | Do not rely on the current Learning tools. | The normal LangCompass explorer and lessons remain fully usable. |
API maturity
Why one tool may work while another does not
Translate
Uses the task-specific Translator API and a pack for the exact German-to-target-language pair.
Summarize lesson
Uses the Summarizer API and a browser foundation model.
Explain and More examples
Use the Prompt API, which requires newer browser and multilingual model support.
Check my sentence
Uses Proofreader when the browser provides it, otherwise the Prompt API. Proofreader availability is still more experimental.
When it does not work
Troubleshooting
This API is not available
Update to the latest desktop Chrome. The normal lesson remains available even when AI is not.
Device requirements are not met
Check free storage and hardware requirements. A different tool may still work because every API is checked separately.
Download does not begin
Use a stable, unmetered connection, restart Chrome, and retry after confirming enough free storage.
A model was available before but disappeared
Chrome may remove models after prolonged inactivity, policy changes, or when free storage falls below its safety threshold.
A target language is unavailable
Chrome checks each language pair separately. Choose another target language or retry after updating Chrome.
Generation is slow
Local generation speed depends on the model Chrome selected and the available CPU, GPU, and memory. You can cancel without losing your source or input.
Chrome diagnostic page
Open chrome://on-device-internals directly in Chrome to inspect model status and current disk usage. LangCompass cannot open or change this protected browser page for you.
Important limits
- Generated language can be incomplete, inaccurate, unnatural, biased, or offensive.
- Repeated output is not proof that a language rule or translation is correct.
- AI results do not replace the curated lesson, a teacher, or professional advice.
- Browser requirements and API availability can change after this page is published.