“The problem with defending the purity of the English language is that English is about as pure as a cribhouse removed. We don't just borrow words; on occasion, English has pursued other languages down alleyways to beat them unconscious and rifle their pockets for new vocabulary.”

― James D. Nicoll

English readily absorbs both the best and worst of all the other languages. If some other language has a word that really hits the mood of even just a small amount of English speakers - bam! - it's English now, motherfucker!

Add to this, it's chock-full of complicated and often hidden rules that can - or absolutely cannot - be broken, depending on context. No wonder people learning it as a second language have that permanently confused look on their face.