1.)they have four different speeds they are walk ,trot,canter and gallop if you want you can incloud jump but thats more of a sport than a speed.
2.)you can train horses to do almost eney thing but the one thing you fisicley can't do is take them in side althoe I have seen them inside on tv.the one thing there good at is sport like polo and of course RACING!
3.)tacking up a horse isn't that importent so why not ride bearback. bear back is when you ride with out a saddle. if your really good you could ride with out your briddle.
4.)If you compet you wear a cotten shirt ,jodphers and riding boots. you also carry a whip. A whip is yoused to mack you'r horse speed up and to slow down pull the riens.
5.)horse colours aren't that colourful only gray (white),brown and black and so on.
And thats whey horses are awesome I hope you like horses.