Reading App for iPad with build-in translator Reading articles in foreign languages is a good and fast way to perfect language skills and I am sure the same thing must have occurred to others before me as well.

I am searching for iOS app for iPad built for reading texts, where, apart from the "define" option for certain words that are available systemwide, one also has the option to translate the word to a given language - in case I am reading foreign text and do not know any particular word.

Ideally the app should support this for PDF's with selectable text, for most of my texts are in those, but if there is no such, I could also convert my PDF's to desirable format.

I checked a number of such apps but so far, but the only one I found with a "translate" option is PerfectReader, which uses Wiktionary as a dictionary; the problem is its vocabulary is practically unusable.
iTranslate Reader does this.  The actual translation function is great - you can use Word Reference or any of several other sites as your dictionary.  Word Reference is an extremely extensive dictionary. The PDF reading function leaves a lot to be desired though - it lacks a bookmark, so when I stop reading and go back later I always have to find my page again. Hopefully they will fix this.

Until then a better solution is Marvin, another ereader app. You can set this up to use Google translate following these instructions:

http://ebookfriendly.com/custom-translation-marvin-book-reader/

I just started using Marvin but it seems pretty good. However you will need to convert your pdfs into epub format using Calibre (which is free, but it's a bit of a hassle to have to do this). I am still looking for the perfect solution.