This is a good question. Let me make a few points that might give you some perspective.
First, verbal communication with a romantic partner has a lot of overlap with verbal communication with other people. This is an important point to keep in mind.
Second, there are some ways in which verbal communication with a romantic partner is different. One of the major differences is that you know that person in a special and exclusive way. For this reason, you will have a "special" vocabulary with that person. For example, the word "honey" might have many levels on connotations that you share with that other person. Or there might be a nickname that you call each other.
Third, in view of your closeness with that person, you will be able to share things that you would not ordinarily be able to share with others. In other words, there is a level of transparency that you share with that romantic partner. There is also greater sense of freedom of speech.