Mervik, This isn't an easy question to answer, which is why Common European Framework of Reference for Languages is created. Though that is still not specific, at least it gives a framework. It also depends on the time someone puts in and their abilities - also the skill of a teacher, if they choose to use one. In English we might ask: 'How long is a piece of string?' Using the Michel Thomas method, I was able to learn enough Italian to travel in about a week (maybe less), but then I know another Romance language to a reasonable level already. Maybe think a bit more about what you want to achieve and look at the CEFR.

I'm going to agree with Colin that there's no easy answer to your question. It depends on way too many factors, like your talent for learning languages, the time you put into it, the resources you use, the languages you already speak. I personally am lacking talent, put in a lot of time, use many resources and already speak 3 languages fluently. With all of this combined I'm now able to kind of have conversations after studying Spanish for a bit longer than a year. Good luck and also, don't forget to have fun!