Several extensions now make the same promise: put two subtitle lines on screen and let you click on the words. They are not the same, and picking the wrong one costs weeks.
Let us be upfront: we make Telidioma, one of the tools compared here. That is why this article sticks to describing what each one does, without inventing flaws in competitors. All four are legitimate tools, and three of them have been around longer than ours.
What these extensions do, in general
They all follow the same basic idea: they sit on top of the player (YouTube, Netflix and sometimes other sites), read the subtitles the site has already loaded and present them in a way that is more useful for language learners.
What changes between them is depth: how many sites they cover, what happens when you click a word, whether there is review afterwards, how much they cost and in which language the explanation reaches you.
Language Reactor
The best known of the group, and for good reason. It started out focused on Netflix (it used to be called Language Learning with Netflix) and later grew to YouTube and other sites.
Strengths: it is mature, stable and has a fairly generous free version. Subtitle navigation is excellent: you can jump from line to line with the keyboard, which is great for intensive study. It has a large user base and plenty of tutorials around the internet.
Limitations: some features are reserved for the paid Pro plan, and its focus is translating and navigating subtitles more than explaining how a word is used in that particular sentence. For intermediate and advanced learners who mostly want fast navigation, that matters little.
Trancy
The one that has invested most in AI features in recent years. It covers a large number of platforms: YouTube, Netflix, TED, Coursera, edX, plus translation of ordinary web pages.
Strengths: breadth. If you study on online course platforms, it covers the most places. It offers grammar analysis of sentences and speaking practice features.
Limitations: the number of features comes with a real learning curve, and the best parts sit behind the subscription.
eJOY
A more explicit focus on building vocabulary and spaced repetition. It has a mobile app as well as the extension.
Strengths: its review system is the most developed of the group. If your problem is forgetting what you looked up, it is the most direct answer. Games and exercises based on the words you saved.
Limitations: the in-video experience is busier than the others, with more elements on screen. And the line between what is free and what is paid changes fairly often.
Telidioma
Ours. It was born from a specific observation: existing tools are good, but the explanation you get when you click a word is often a dictionary entry, not an answer to “what does it mean here”.
What is different: the translation is done in the context of the sentence, not word by word, which avoids the classic problem of “get” being translated as “obtain” in a scene where it means something else entirely. Each click brings the meaning in that sentence, the part of speech, a definition and an example. Outside video, you can select a word on any website and get the same explanation. It was built first for Portuguese speakers, with explanations in Portuguese and false-cognate warnings for them; everyone else gets the explanations in English. Study languages include English, Spanish, French, German, Italian, Japanese and Korean.
Where we are still behind: our subtitles work on YouTube and Netflix, while Trancy covers many more video platforms. Our review system is simpler than eJOY’s. And we are the newest, with less track record than the three above.
Side by side
| Language Reactor | Trancy | eJOY | Telidioma | |
|---|---|---|---|---|
| YouTube | Yes | Yes | Yes | Yes |
| Netflix | Yes | Yes | Yes | Yes |
| Other video platforms | Some | Many | Some | No |
| Translation that considers the context | Partial | Yes | Partial | Yes |
| Vocabulary review | Simple | Yes | Full | Simple |
| Mobile app | No | Yes | Yes | No |
| Free version | Generous | Limited | Limited | Limited |
How to choose
If you are already intermediate or advanced and want fast subtitle navigation without paying anything, Language Reactor does the job very well.
If you study on online course platforms like Coursera or edX, Trancy covers the most places.
If your main problem is forgetting vocabulary, eJOY was built around that.
If what you want is to understand each word in its sentence, with a short, clear explanation and the same tool on Netflix, YouTube and any website, that is what Telidioma is for.
And one honest suggestion: they all have a free version. Install two, use each one for a week on the same kind of content and keep the one you actually opened on day five. A study tool is not chosen from a comparison table, it is chosen by which one you keep using once the novelty wears off.
What none of them do
Worth saying, because overpromising is everywhere in this market: no extension will make you fluent. They remove the friction of looking up a word, and less friction means you look up ten words per episode instead of two. That speeds up vocabulary and comprehension a lot.
Speaking is another story. Listening builds the raw material, but producing sounds is a separate muscle that needs its own training, whether through conversation or shadowing, which means repeating out loud along with the video. More on that in how to learn English on YouTube.