Diplomatic language

I took an English lesson yesterday as usual, and treated topic was "diaplomatic language," as I wrote in this tytle. I was not sure about this term, indeed (-_-;). Certainly, I knew the word like governmental people who went abroad and negotiated with foreign people. We say that they're "Gaiko-kan" in Japanese. Roughly speaking, "diplomatic language" is polite wording as follows:

Direct: We have a problem.
Diplomatic: We assume that we have a kind of problem.

In general, we often use some special words like "a kind of", "slight(ly)" or auxiliary verb: "could", "would" and so on. In such a situation, we have to imagine actual situations, i.e. if we use "direct wording," how is the suitable expression?

I usually exchange opinions with foregin people in my work, and certainly, am using "diplomatic language." At the beginning of current work, my suprevisor pointed out my "direct wording," and she said that I had to use "diplomatic language," in case of exchange our opinions with foreign people, though she didn't say to me that they were called "diplomatic language."

In writing this article, I remembered my current work at this moment... (-_-;)