I'm reading "Victims No Longer: The Classic Guide for Men Recovering from Sexual Child Abuse" by Mike Lew and he discusses his interactions with victims of sexual child abuse and their tendency to ask the question above.
I've had this same experience with people who have lived through traumatic or seriously dysfunctional childhoods. They express a lot of uncertainty in their ability to communicate what they mean and their ability to be understood by others. They also tend to be very uncertain about their own beliefs, opinions and judgements. I'm constantly asked, "Do you understand?", "Am I making sense?", "Is that crazy?". When I listen carefully I hear these phrases peppered throughout their speech and when they relate interactions they have had with other people they reveal that they use these questions with everyone in their life.
Lew posits that this is the result of abuse as a child, and he makes a good point. Children who grow up in abusive homes are sworn to secrecy. They grow up knowing their families are different from other families. This is especially true if they are sexually abused. They almost have to lead a double life, the facade they put on when they leave the house versus the reality when they return home.
But I think it can also be related to denial in the family system. I know for myself and with clients with whom I have worked, if you grew up in any family when tells you, "that didn't happen". You soon question your ability to discern what is true. You learn not to trust your five senses. You could have sworn you heard your parents arguing, but they tell you it didn't happen. You could have sworn you saw Mom crying, but she denies that anything is wrong. You could have sworn you saw that Dad was not sick, but was too drunk to go to work yesterday. But you are told this is wrong.
So you grow up constantly seeking second opinions and taking polls. You grow up knowing you live in a different kind of family than your friends. You grow up knowing that there are secrets you hold which cannot be told. And you learn to live two lives. You don't actually live a normal life, you fake it. So you are always wary of getting it wrong, making a misstep. This uncertainty shows itself in how you present your ideas, opinions or information in general, "Do you know what I mean?"
For male survivors of sexual child abuse I heartily recommend Mike Lew's book, "Victims No Longer: The Classic Guide for Men Recovering from Sexual Child Abuse ."