I have been using Google Translate app for a long time. It's very nice the constant improvement of its features. But now, GTranslate give us a big gift: it works from inside others apps!!
GTranslate has an update in Google Play with this magic. It's possible to use this new feature if your device runs Android 6.0 Marshmallow. Now, we don't have to copy/paste each time we need some help iin languages. It's easy to use: highlight the text from inside any app and GTranslate shows a pop-up window with the translated text. Simply, hum?