Biro is a trade name for a kind of ballpoint pen (invented by a Mr Bíró), which was widely used in the UK for ballpoint pens in general, though not so much now, I think. A bolígrafo is also a ballpoint pen, so it's actually quite a good translation - if you're familiar with the word!
If you use the text to speak function on your phone's keyboard and add spanish as a language you can practise your pronunciation there as it is able to pick up bith sentences in Spanish and English then but only when pronounced correctly will it pick it up correctly. It's a good way to practise.
Why is Duolingo so obsessed with pens and libraries? this seems like an extraordinarily slow pace to learn new words. right now they haven't used many common words that would make sense like paper or notebook. I don't know if this is the way Spanish is normally taught and although I like to move slowly it seems like they are dragging their feet