In the case of the Dudley name, we do not have many problems.
ALL the founding Dudley's were nobles, (Barons). And this is where we begin our story.
John de Sutton was given some land by the king, as a reward for John's services to the king. The land given to John was was known as Dudda Leah or Duddas Land, later changed to Dudley as we all know, from the story above.
When John took processions of this land, he became known as Sir John de Sutton, Lord Dudley. The Sir because he was a Knight, in the Order of the Garter. de Sutton to designate his origins, (remember the story above?) John was from a place called SUTTON, FOUNDED BY  SUTTON NORMAN ANCESTORS, Now de is a French or Spanish word, meaning of, so we have Jean de Sutton, or John of Sutton.
Now John was called Lord Dudley, because he was the Baron over the land of Dudley. Now as a noblemen's social standings goes, a Baron was called a Lord. Just as a knight had Sir at the beginning of their name, a Baron would have Lord at the beginning of his name.
Now since John was owner and master of the land called Dudley, his title was Sir John de Sutton, Lord Dudley, Baron of Dudley.
Now, here is where it gets confusing. John Sutton II, married Isabel de Charlton and had several children. When John died in 1359, Johns and Isabel's children stayed on the land, and at the time kept the Sutton name until around 1420, when they started using de Dudley as their last name. Later they drop the de off and started using just plain Dudley, as their last name, doing away with the Sutton name altogether. Now, these Dudley's kept the lands and Dudley Castle, and where called Lords of Dudley or Barons of Dudley, and are known in the Dudley family history, as the Second House Dudleys.

Okay, what do I mean by the second house? You'll have to pay close attention now, as I try and explain this Second House.
Shortly after Sir John de Sutton II (Dudley), "Lord Dudley died in 1359, (Grandfather Dudley?) Isabel de Sutton (Dudley) remarried to Richard de Dudley (Grandfather Dudley?) and moved to live with her new husband, Richard Dudley in 1361, and had several children with Richard. These children of Isabels and Richard, immediately assumed as their last name, Dudley. These children became known as the First House, simply because they took Dudley as their last name first. Remember, John and Isabel's children didn't start using Dudley as their last name until 1420. Some 38 to 39 years after the children of Isabel and Richard's children became known as Dudleys.
So, we have John and Isabels children as the Second House Dudley, and Isabel and Richards children as the First House Dudley.
Now, all Dudley's, with Euro-English or Euro-American ancestors, come from these two Houses of Dudley. They had two different Fathers, John and Richard, but had the same Mother, Isabel. Which I guess you can say, all Dudley's are related, being we had the same Grandmother, Isabel. This is how the Dudley family began, and we are now world-wide, with Dudleys living in almost every country in the world.
Well, one thing about it anyway, if you are still un-clear as to how we became Dudley's, at least one thing you have learned, if you are a Dudley is, you have found out who your Great-Great-Great-Great-Great-Great-Great-Great-Grandmother was, Isabel (de Charlton) Dudley. Now, which Grandfather or line do you or I come from, is your Grandfather John de Sutton, or Richard de Dudley? Well that, you'll have to find out by a lot of researching and by looking up your ancestors.