Vtudien

Vtudien is a free online dictionary site built around Vietnamese, useful if you’re learning Vietnamese through English (or other languages) and want quick lookups with examples and pronunciation.

The core is a set of bilingual dictionaries like English-Vietnamese and Vietnamese-English, plus many other language pairs (Russian, Lao, Chinese, French, Korean, Japanese, and more). Entries can include pronunciation and a mix of general and subject-area terms, so it’s handy when you’re reading and hit unfamiliar vocabulary.

If you want a desktop workflow, they also offer a Windows dictionary program that supports hotkeys for looking up selected text and even looking up text in images or on-screen content. That can be convenient for heavy reading, but the Windows app’s SourceForge page shows the last update was in 2019, so don’t expect fast-moving development.

This is best as a reference tool, not a structured Vietnamese course. It won’t guide you through a learning path or give speaking practice, but it can speed up reading and vocabulary building.