Do 2 medium UVs on Armor and Helmet = Very High?

I have a Vog Cub Coat and Cap. Both give me a Sword Attack Speed Increase of Medium. Does that mean that they combine to give me a sword attack speed increase of Very High? And if so, would a sword UV of Attack Speed be wasted since Very High is the highest you can go to?
The Vog's bonus is just considered an "Armor Bonus" not a "UV" which stands for Unique Variant. A UV on Vog would be something like UV Poison Medium.
They will stack, giving you Medium (2) + Medium (2) = Very High (4) ASI for Swords.
UVs in weapons can only go up to Very High... but the bonus can extend all the way to Maximum which has a value of 6. So if you are wearing full Vog you already have Very High (4) and would only need a Sword with UV ASI Medium (2) in order to reach a Maximum (6) ASI on the sword. A sword with Very High (4) would total beyond the Maximum cap and thus be wasteful.

So if my shield also adds to the attack speed by medium, then the helmet, armor, and shield combine to make 6 - the maximum allowable and completely eliminates the need for a speed UV. Amazing info!

if you're referring to the swiftstrike buckler...
that's actually ASI High, so you'd be +7, over the max
In your Character status screen, highlight the bottom symbols, it lists the cumulative abilities of all your equipment.