Iori said:
Firstly, how could a single state comprised of the lands surrounding the English Channel come to be?
Well, the first way to achieve that would be the classic Anglo-French Union. There are plenty of scenarios, and it would end with one country controlling both sides of the channel.
Besides the Anglo-French Union, I think we could see a Norman Kingdom rise in that area. After all, the Normans were given Normandy by Charles III of Western Francia. They also had Britanny under their thumb for a short while. William the Conqueror was Duke of Normandy before he became King of England. And one of his descendants, William Clito (son of Robert II of Normandy, William the Conqueror's eldest son), could have become Count of Flanders at one point. This surrounds most of the area on your map.
Another solution I can think off would be one man inheriting all the feudal lands on both sides of the channel but in early medieval times. I'm thinking of some sort of Henry II of England scenario but limited to the channel.
Iori said:
Secondly, assuming it's not created out of some revolutionary process that would fundamentally change Europe,
what would be the effects of a Royaume de la Manche* on Europe itself and on exporation and colonization?
First, unless it is realized by an Anglo-French Union, you will get weaker Kingdoms of France and England. However, given its position, the
Royaume de la Manche will probably be influenced by the events in both Kingdoms.
Second, with the Channel being in the total control of the
Royaume de la Manche, it could be a source of income for that Kingdom. That would probably affect naval trade in the area.
On colonization, there is a good chance that this
Royaume de la Manche becomes a colonial power given its position.
Iori said:
* It does'nt have to be French derived, Royaume de la Manche just sounded better than Kingdom of the English Channel or Channel Kingdom.
Well, that Kingdom has good chances of speaking French. The Normans ended up talking French when they got Normandy and most of the lands in Northern France spoke French or French-derived languages. As for Southern England, it is close enough to France to be under a linguistic influence, especially in a scenario where the Channel is controlled by the same country.
Of course, you could also end up with a new language. Some sort of Anglicized French or Frenchified English.