Alright, just to settle it once and for all so there is no confusion:
Two Handed Weapon Style gives general improvements towards wielding melee two handed weapons such as spears, halberds, or indeed two handed swords. Putting points into this will improve the hit chance and the speed you use the weapon. This does not apply to ranged weapons, only two handed melee weapons. Putting two points into this slot will also increase your chances of scoring a critical hit with 2h weapons, that is
very good!
Sword and Shield Style style improves your skill at using a shield, or in game terms, gives you a bonus towards deflecting arrows and other projectile weapons. Pretty straight forward really. Shield = Hard to hit. Putting points into this improves that effect, although you don't gain any offensive bonus.
Single Weapon Style style is for wielding a single
one handed weapon and no shield. Improves your hit, damage, and speed the more points you put into it. Essentially if you wanna go at your enemies Kill Bill style, this is it. Doesn't hit as hard as a two handed weapon, but it hits faster and more consistently the more points you put into this specialization.
Two Weapon Style. Here's how it works: If you use two weapons at once, you receive a lowered chance towards actually 'hitting' with those weapons since essentially you're swinging twice as often. Someone with no points in this talent trying to dual wield longswords for example, while badass looking, isn't going to hit much. Putting points into this talent simply reduces that hit penalty. That's all!
So the different between Two Handed Swords specialization and Two Handed Weapon Style is simply that the swords one will *only* improve your skill with two handed swords, whereas the general two handed style improves your general performance with *all* two handed weapons by making you hit more often as well as faster and with a higher critical chance.
And yes, the bonus stack, so it's good to put points into both.
Choosing a specific weapon, and a weapon style is the best approach at first. Later on however, especially with Fighters, you get enough points to diversify more but for early on its best to specialize.
