[sentence] + 吧 / 呢 / 啊 / 嘛
吧, 呢, 啊 and 嘛 sit at the very end of a spoken sentence. Each leaves the content alone and sets the speaker's attitude: a guess or suggestion, an open question, a reaction, or something the listener should already know. 你去 takes three of them:
On a statement, 吧 says you think it's true and want it confirmed. On an instruction, it softens it into a suggestion.
呢 goes on questions that already have a question word or an A-not-A choice like 去不去, and makes them sound like you're wondering rather than demanding.
On a statement, 呢 says the situation is still going on, or pushes back on what the listener assumes.
啊 adds warmth, surprise or impatience. On an exclamation it is the emotion; on a question it sounds more insistent or more friendly, depending on the voice. After some sounds it is written 呀, 哇 or 哪; that change has its own point.
嘛 presents the sentence as something the listener should already know. It can sound reasonable or a little impatient. On a request it coaxes, the way a child pleads.
呢 doesn't turn a plain statement into a yes-no question; that is 吗. 嘛 sounds like 吗 but never asks anything.