Design, style, colors can have a specific meaning in a specific culture.

For example, in a western culture, where the language is written from left to right, we assume that what is one the left comes before than what is on the right. Okay... why should you care?

Imagine you are building a navigation bar with the titles of the main pages of your app. In western culture, you would expect to have the home page button on the left, as this would be the first page you see.

Another simple and silly example is color. In many cultures, red is used as a color for signaling dangers or grabbing attention. Road signs signaling dangers or signaling forbidden stuff are in red.

That's why in this type of culture the color of buttons can already convey meaning.

Obviously, what is true in a culture, isn't always true in another culture. That's why testing your app with real users from the specific culture you are serving is important.