Probably quite a few. New things happen. Politics, wars, famous folks, movies, music, diseases, scientific studies, products, brands, model numbers for products, fads and slang. I'm guessing there are other things as well.
Some of the new things are probably variation as well - as others have mentioned, sentences and voice commands can give lots of new stuff.
Some of the new things are probably variation as well - as others have mentioned, sentences and voice commands can give lots of new stuff.