Word Highlighter by Vocabulary Level is a Chrome extension designed to aid language learners and improve reading comprehension. This free tool utilizes a three-color highlighting system to categorize words based on the user's vocabulary knowledge: green for known words, yellow for partially recognized words, and red for unknown words. This intuitive visual aid helps users identify which words require further attention, making the reading experience more efficient and engaging.

In addition to its smart highlighting features, the extension includes interactive word tooltips that provide instant actions, personal vocabulary management, and options to import or export word dictionaries. It is customizable, supports dynamic content, and maintains user privacy by storing data locally. Suitable for language learners, students, and professionals alike, this extension transforms reading into a proactive vocabulary-building exercise.