If you have extra money, it may be cheaper to sell and buy back items from a merchant repeatedly to gain experience than to make use of one of the Speech trainers. It only counts for the first item, so sell expensive stacks of items one at a time. When you sell an item to a merchant, you get skill experience based on the cost of that item. This also allows you to bribe your way out of trouble with guards, if your bounty is low enough. Second, it helps with Quest progression by giving you a chance at passing dialog option checks and advancing a quest by persuading, intimidating, or bribing. First, it helps your Dragonborn to make more money through higher prices selling to shopkeepers, cheaper buying prices when Haggling, selling stolen goods, and can even let you permanently increase the gold available to a merchant for bartering. Skyrim's Speech skill fills two roles in the gameplay. Skyrim Speech Guide Speech Skill Tips, Trainers, and Perks