Spanish Encounters At Work

When I am working, I usually am the cashier. When I am the cashier, I encounter many types of people. Lately, I have noticed that there are a few customers who speak Spanish. One time when I was working, there was a spanish family that came to my check out. They were talking in fluent spanish to eachother, but when they were talking to me it was in english. I was suprised as to how well they spoke english, and how well they understood me. One thing that I found was interesting was that when the family was talking to eachother, I could understand and pick out some of the words they were saying. I could really tell that my years of being in spanish have paid off.