What's the most important language in business?
ANSWER: Your customers language!
When I was coaching football in Italy, the most important language was Italian. Even though the game was taught in English, with English terms, it was translated into Italian by all the players.
Just like your customers, they will translate everything you say into their language, so make it as easy as possible on them so that nothing gets lost in translation. In order to connect with others (customers) you have to forget yourself.