Yes, fika has a 'long i', but ficka has a 'short i', short vowels are as a rule followed by a double consonant, it's just that 'k' is an exception spelling-wise, we write a double-K as ck

Well, a book small enough to fit in a pocket, more or less. So here we use the English expression "Pocket book", but shortened to just pocket

It doesn’t work on mobile: https://www.duolingo.com/comment/6141931