I've also noticed this while learning Chinese -- I think quite a bit of the initial difficulty with learning a second language is just training your brain what to expect next.

Going into a 711 to get a coffee in Taiwan you know approximately what questions they are going to ask: size, hot/cold, do you want a bag (to hang on your scooter), and do you want a receipt.

Similar with the supermarket, a restaurant, when getting train tickets, etc.

You're just building up what questions to expect next for the scenario -- if the conversation deviates from that (even with words or questions you might know) your brain has a hard time initially adapting to that.