Imagine describing a funny movie to your friend. Now, imagine describing that same movie to the president of a large corporation. Would you use the same language? It’s unlikely. Humans are skilled at gauging when to use formal language vs. informal language. Machine Translation (MT) engines are generally unable to do so — unless they have help.
It’s imperative to be aware of this MT limitation and take steps to overcome it to develop a strong relationship with your target audience.