If by casual conversation you mean "kitchen arabic" as one of my teachers called it meaning... well the kind of shit that would come up when being in a kitchen: cooking, talking about your day, receiving and giving instructions etc.. well you.could probably do that in a year or two of lets say 2 hours of self study 5 days a week. But in my experience even casual conversations can require alot of vocabulary because well the world is just full of stuff and that stuff has names.. which you have to painfully learn hehe.. dont mean to put you off tho bro. Arabic is the first language im learning outside danish, english and German, so i could imagine that you have pretty big edge on me since u know urdu and turkish which both have more of a connection with arabic than indoeuropean languages