Just as an aside, Where do the Friesians come into the equation…
I am willing to except that the reason English is so close to Frisian is because perhaps all the tribes of the time and region spoke a similar language to that branch of German but they were already there when the invasion started and the invasion had to pass through their homelands in Germany to get there. It is likely they had better technology due in part to their service to the Romans as well as being noted traders as well as the forerunners to the Vikings as sea raider and were very advanced in shipbuilding.

I have been wondering of late if the Norse didn’t get some of their ship technology from them and perhaps some of their smithing to go with it.

Back to the Saxons now, if they were using pattern welded blades in the invasion period why was it said that this was part of the Viking military revolution and made them so strong?

I don’t know what you know about metallurgy but that welding was a big deal as it gave the iron hardness and stiffness that plane iron would not have. In fact what makes steel different than iron is that little bit of carbon interspersed in the crystalline structure of the iron which imparts its hardness, ability spring back into shape and to hold a temper for a better edge. Hammering that iron gives it work hardening and puts a bit of carbon into the iron giving it better properties as a weapon. It is a delicate balance though because too much carbon…only around 1%…makes the iron unweldable and brittle.