Screaming is usually without words, if someone is attacked, they "scream". You can scream using words, but usually we say 'yell' or 'shout' in that case. Yelling is using speech. If someone is talking really loud, you say, "don't yell, I can hear you!" (the opposite of yelling is whispering). Shouting is the same as yelling - speaking something in very high volumes. Whereas screaming is not always speech - a common thing to hear in a horror movie is a woman "screaming". I think shout and yell are probably interchangable, i can't think of a situation where you can't use one or the other. I think we use 'shout' more than yell, usually we use yell when we say "Don't yell", like children who are talking really really loud, we tell them 'don't yell'... but 'dont shout' has the same meaning, really. Vent is 100% different. A vent is something that air can go through. In a house or building, there is usually a small area where the cool or warm air enters a room, that is a vent. Figuratively, "to vent" means to let out hot air - like ifyou are angry, you let some of that hot air (anger or unhappiness) go out of you, so that you calm down. Usually, you "vent" (by talking to someone about your situation, for example) so that you won't become some angry that you might scream! :)

scream, yell, and shout are quite similar i believe vent (one's feelings) in spanish = rienda suelta a sus sentimientos

Examples: She wanted to scream at her employer because he made her work overtime. The man tried to give vent to his emotions by kicking his poor dog. Don't yell at me from the bathroom, walk into the lounge room and tell me what you want. They wanted to shout at the umpire as they felt that he favoured the opposition.