Okay, how about in the 500s the Finns, instead of migrating to Finland, stay in Central Asia and are absorbed by the Mongols. Thus, when the Mongols go world conquering, they have more men, allowing them to crush Persia and wipe the Magyars and Bulgars out. They move farther into Europe, really messing up the place before the Khanate falls apart. Bulgaria is partitioned between Serbia and a Beylik state, Armenia and Persia rebuild but never recover, and Hungary is absorbed into a Polish-Bohemian union while England and France assimilate their Celtic speakers, except for a few holdouts in Dumnonee and Connaught. Colonisation occurs differently due to butterflies, with a stronger Mughal Empire colonizing Madagascar, and the Africans being made to speak European languages like the Native Americans are. I can't get more detailed than that because this is a linguistic map, not a political one.