This is a very important question since it is about achieving the most assertive, effective and clear communication possible to close successful deals.
To answer it, we first quote Willy Brandt, former Chancellor of Germany:
To clarify, the phrase in English reads like this:
“If I’m selling to you, I speak your language. If I’m buying, then you have to speak German”
Although we believe that the phrase does not need to be explained, we think the most important factor is to highlight that, when one needs to communicate with audiences that do not speak / understand one’s language, it is very successful and culturally respectful to facilitate as far as possible the communication for such audiences. Besides, you must ensure that said audiences clearly understand the message to avoid critical misunderstandings.
It is very essential to keep in mind that thinking and speaking in your language is an excellent good practice to ensure the quality of communication and reduce the risk of misinterpretations that may cause loss of money, time, reputation or legal problems.