>>11840359
It's actually extremely different, niggerfaggot.
Speechcraft and Personality affects Disposition, and further your chances for succeeding at Persuasion (Intimidate, Admire, Taunt, Bribe), and Disposition affects a number of quest interactions (some quests require you to get a high enough Disposition towards you), and whether or not some NPCs want to talk to you about some things.

For Disposition making the difference over a neutral NPC being hostile towards you, it can, but there'd likely have to be multiple of the following factors in play at the same time for this to happen:
>different race from them and having your weapon out will both automatically decrease Disposition
>you have an extremely shitty Personality attribute
>you try repeatedly to Admire them, but you continuously fail and they hate it, eventually they'll anger from this
>you have negative Reputation (ergo you're a wanted outlaw with a price on your head)
>you're in an opposing faction
This can further affect their Fight value, a hidden metric which determines how likely an NPC is to turn hostile. Things increasing an NPC's Fight value would be if they caught you committing theft or trespassing (particularly against themselves), or they saw you attack someone else neutral. If you wanted to pacify a hostile or likely to be hostile NPC or creature without violence, you would use a Calm spell.

Mercantile in Morrwoind is used for Barter, affecting prices for Trading (as well as Bargaining when Trading), and prices for services (Repair, Training, Enchanting, Travel, Spellcrafting, buying Spells). Mercantile also affects your chances of success for Bribing. Needless to say, Disposition also affects pricing for these things, thus Personality, Speechraft, Reputation, etc, would also affect these things.