The Drunken Lizard Pub

I did not buy it at the beginning of the game. Is it possible to learn it from someone? follow up question: how do you learn a new skill?

You can either learn the skill on your next level up by spending 3 skill points to purchase a new skill, or you might find a book in the wilds that will teach your for free.

...Also, in some places you'll find trainers, who'll teach you skills for a price.

They won't be able to teach you, however, if you've already attained a certain level in that particular skill.

...But don't hold out on learning skills that are valuable to your character with the hope of running into a book or trainer soon . . . at least, not until you've played the game through once already and therefore know what you're doing.