google knows, it's just the advertisers that use their services don't care enough to filter audience by language (or think it's not worth it, sometimes images are enough to entice customers...).
It really depends. After going on a month-long trip, Google was serving me ads in German, as well as offering Google Photos printing expecting a German address with the price in Euros, all despite us never entering Germany, let alone staying there long enough for it to assume permanent residence. This continued for about 6 months after.
