Foreign languages and ze Swiss

Few people surprise me, positively I mean, but this morning the phone rang. It was one of the guys who owned the plot of land where my flat is being built. He told me that the exchange of contracts will take place on 31st of August, which I knew, but it didn't matter. I was nice to get a second confirmation. And he did it all in my mother tongue! A Swiss guy! Now I'm really curious to find out why he has bothered to learn a minority language...