The Japanese word for yes is hai. The Japanese word for no is — well you don’t really use the word for no in Japanese. The Japanese still say no. They’re just not crass enough to use the word no itself.
It’s like that in English, to a lesser extent. People will say no in various ways, usually without using the word no. An important part of nonverbal communication is understanding what people are really saying, especially when they’re being politely indirect. Specifically, it is our responsibility to hear it when people tell us no politely.
Saying no is an important part of boundary setting. In fact, most boundary setting is learning how to say no to people. To set proper boundaries, we must tell people when they’ve crossed our boundaries, and even when they’re getting close.
However, using the word no is often impolite. So people will use other phrases, like, “I don’t know” or “I’m not sure about that”. Or people will give reasons for why the answer is no and leave it to the listener to make the connection. They are still saying no, just without the actual word no.
I used to not pick up on when people told me no, especially if they didn’t use the word no. I’d think we were discussing the merits of different alternatives. We’d bring up reasons for and reasons against, to help us make a group decision.
The people I was talking to saw it differently. They saw it as they were saying no by bringing up objections, and I was shooting down all those objections. In the end people would get tired of fighting me and just agree with whatever I was saying.
I’d leave the conversation thinking we had made a collaborative decision.