Product guide

How WordHalo works.

Install the Chrome extension, choose “My language,” and highlight any word or short passage on an HTTPS webpage. WordHalo detects the language of the highlighted text, then shows a translation, a learner-friendly definition, an in-context explanation, and pronunciation audio in a card beside your selection. Words you save are kept on your device and reviewed with flashcards and learning games.

Step by step

  1. Choose “My language.” This is the only language setting. It controls the interface and the language of translations and explanations.
  2. Highlight text while reading. One word gives you a definition-style card; a passage up to 500 characters gives you a summary-style card.
  3. Review the first-use disclosure. WordHalo sends the highlighted text and up to 1,000 characters of nearby context to its service only after you agree. It never sends your full URL or browsing history.
  4. Read the help beside the text. Tabs cover Translation, Definition, and In Context. If the text is already in your language, the Definition tab opens first and the redundant Translation tab is hidden.
  5. Listen and save. The speaker button pronounces the selection in its detected language. The heart button saves the word with its translation, definition, context, pronunciation, and example.
  6. Practice later. The My Words page organizes saved words by detected language and offers flashcards and learning games — locally, without an account.

How does the review system work?

Flashcards show the saved word first; you reveal the translation, definition, pronunciation, and example when ready. Choosing “Practice again” schedules the word about a day later, while “I knew it” pushes it further out — from two days up to a month as your review count grows. Words progress through New, Learning, and Mastered states. Spacing reviews out this way follows a well-replicated finding in memory research: distributed practice produces more durable recall than massed practice (Cepeda et al., 2006).

Why explain words in context?

Seeing a word inside a real sentence, with an explanation of what it means right there, supports the incidental vocabulary learning that happens naturally during reading (Nation, 2001; Webb, 2008). WordHalo keeps you inside the sentence instead of sending you to a separate app, so the context is never lost.

What are the technical details?

  • Manifest V3 Chrome extension requesting only the storage permission.
  • Works on ordinary HTTPS pages; Chrome blocks all extensions on browser-internal pages such as chrome:// pages and the Chrome Web Store.
  • Selections are limited to 500 characters; AI reading helps on the free plan are limited to 15 per day.
  • Saved words, review progress, and game statistics are stored on your device with Chrome's local storage.
  • AI results can be imperfect. The AI disclosure explains where they can be wrong.
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