Is this true about guys?

It sounds to me like the article explained it pretty well. Guys simply aren't very talkative. At the beginning of a relationship we talk more because we want to impress a girl. Once we are comfortable though we talk less. Its not that we don't want to talk to you, its simply that men just aren't as talkative as women (with some exceptions of course). It can actually be taken as a compliment to you, or to the relationship, when we start talking less. Less is the key word though. If the guy stops talking all together that is clearly a problem. One thing the article doesn't mention is that when a guy has an idea or does something that they feel proud or excited about they will still share that with their woman. If the guy is not still doing that on occasion then there may be a problem. Just talkin a little less though is not necessarily a sign of a problem.