Popup dictionary

I thought this setting was determined by the first Language of Study dropdown box in your profile. But since lang-8 is a Japanese site, maybe it only does English<->Japanese? I'm not sure now.

Did the popups translate to Polish before and then switch to Japanese? Or have you only seen the Japanese ones?

I don't know if it's possible (yet) to get anything other than Japanese-to-English on the Lang-8 pop-ups, but there are certainly websites where you can look up such things.

For English-English I usually recommend dictionary.com or en.wiktionary.org. The former usually has more definitions (because it draws from a variety of sources) and also features a thesaurus, but Wiktionary is good too and will also give you English definitions for words in other languages, e.g., I use it to look up Japanese words sometimes.

For English-Polish you could try Babelfish (babelfish.yahoo.com) or the Polish Wiktionary.

It should be possible to create bookmarklets to take the word you currently have selected (highlighted) and look it up in a new tab or window. Let's see... something along these lines perhaps...

javascript: x = escape(getSelection());
if (x.length) {
window.open('http://pl.wiktionary.org/wiki/' + x);
}

It might even be possible to create a browser extension to do lookups on those sites and pop up the results overlaid on the current page somehow, similar to the Lang-8 pop-ups, but my knowledge of XUL isn't up to the task.