I have decided that I will make a point of buying books in my own language (Swedish). It's not that easy anymore. When I was a child, I was given plenty of great books on birthdays and Christmas. My mum had bought me so many books, before I could even read, so I had a head start on my Swedish book collection. These days I struggle to find good books in Swedish. The 'toplist' is artificially made up by the big publishers. It no longer consists of the best selling books, but the ones the publishers would like to sell best. And apparently, their criteria for publishing a book is not quality, it's saleablity.
However, I'm doing my best looking for Swedish children's and YA books, non fiction and - naturally - fantasy, science fiction and mysteries. They're usually more expensive than books in English, naturally enough, since the editions are much smaller. I usually can't find books of the very highest quality either. It's sad, but true. But I really want to have a Swedish book collection so it's going to be worth it in the end. I also want to have smaller collections of French and German books, maybe others too. Fortunately, those aren't usually that much more expensive than English/American books. Clearly, French and German are big enough languages to produce large enough editions of every title.
My 'policy' when it comes to book buying is to, as far as possible, get books in the original language, and if I can't read the original language, the one I know best. I'll make an exception if the Swedish translation is far less expensive than the original. Some years ago, there was this Chinese book I really wanted to read. Naturally, I can't read any Chinese language, so I looked around for an English translation (unsurprisingly there wasn't one in Swedish), but there wasn't one. Fortunately, there was one in French, so I bought that.