Some Google tools come in quite handy for foreign language learners. I use Google Chrome, even so the following tips should work equally well with Firefox.
Install Google translate browser plug-in and you can get instant translation of any webpage with a mouse click. You can configure which languages you want to use. Google translate is anything but perfect but when it comes to machine translation there is probably no better tool (not even among paid ones).
Google dictionary plug-in
Much more useful than google translate is Google dictionary for language learners. If you install the plug-in all you need to do is double click an unknown word and you get a call-out telling you the meaning of the word and its pronunciation (audio).
Google voice search to practise pronunciation
Users of android phones probably are familiar with voice search. Now it is possible to have this feature also in Google search on the PC or laptop. There is no plug-in to install. However, to my knowledge the only language supported so far is English. You need to change the search settings to English language in order to be able to use this feature. You can use it to practise your pronunciation. It’s not perfect, but it does a nice job.