How different is it to learn to play the violin left-handed?

You cannot get a violin from a right-handed violinist and start playing. Chin-rest for lefties, Strings on opposite sides (thinnest string(E) closest to your left hand), Peg position modification and left-handed bowing. These are the differences. So, yes. You can play left-handed. But you need to get a left-handed violin. It is better to buy a left-handed violin rather than doing it all by yourself being a beginner. The tutorials are generally for right-handed violinists but it shouldn't be difficult. Regarding trying with your right hand - if your right hand is very passive, then avoid it. So, yeah, you need quite some effort to get started. But trust me, you will never regret it once you get to a decent level..

Unless you are a very extreme leftie, its better to learn it right based on the following reasons,1) right handed violins are readily available so you can buy an inexpensive one to start with, leftie instruments require a bit of customization, so you may need to pay more, and have less options where to get them.2) most teachers are playing and teaching right-handed, it may or may not feel awkward for them to teach someone left-handed.3) If you ever plan to play with a group im future, having your instrument pointing the other direction doesnt look very nice visually (unless you're like the soloist standing on your own then its a different story)4) lefties have the advantage of picking up fingering skills faster than righties, but needed alot more work to train up the bowing.  Many righties like to say that lefties have the advantage because they struggled with the fingering, but forgetting that lefyies have to overcome the bowingI am ambidextrous and play the violin right-handed though, so I just dont have any added advantage on either hand, but possibly not much hurdles to go through either. 

After you become ambidextrous in one avenue, i.e ive successfully learned to play lefty and right,  there stops being a line and its all grey area. Left handedness/right handedness fade away after learning both ways, its just both. It actually does help the mind learning things with the opposite hand because its you, teaching you. Mentally you break down the procedure for playing the instrument and you teach  yourself how to play anew. Its a good way of learning subtelties of the craft.

You cannot play a regular violin left handed--  you must use a specially built left handed violin.  They are rare, but they do exist, and should not cost more than a standard violin.  You probably will not encounter many difficulties after you get your violin, since most accessories like bows, cases, rosin, mutes, tuners, etc. are the same for left and right handed violins, and a luthier should be able to repair a left handed violin just fine.You might want to consider whether you really need a left handed violin.  While it is generally accepted that it is desirable to bow with one's dominant hand, both hands have a major role in violin playing, and depending on the exact nature of your handedness, you may feel a right handed violin is just as good.Playing violin left handed is very unusual; people may think you are weird (or perhaps they'll think you are interesting!) and you might have trouble getting into orchestras, but for a hobbyist this should not matter.As to learning from Youtube videos (or any other resource or a teacher), it is sort of like asking if a right handed baseball coach can coach left handed players.  The answer is of course yes, since everything is symmetrical, though it may be slightly more confusing than if both teacher and student were same handed.

I think a right handed person should use the left hand for strings and the right hand for the stick, as the right has to do a lot of timing and precision. Try throwing a ball with the right hand and then the left. While writing too, what the left hand misses out is the precision. Feel the difference of precision in where to let the ball go and the angle. Same would be the difference, as to how far to go with the bow. If people can learn to write with both the hands, (handwriting , I believe, is the most complex and precise of human endeavours; medical operations and jewellery making being the others.) sure can a right handed person learn to play violin left handedly. But it would be as tough.

Recently, I started teaching myself to play the violin in the left-handed style (holding the bow in my left hand) since I am a ‘lefty’. It felt natural to me to hold the bow in my left hand.If you google around a bit, you’ll find that a very few people make violins specifically designed for lefties. So, most probably you will have to buy a right handed violin and tweak it a little to make it into a left handed one for you to be able to play it. It’s pretty easy to do so: You need to reverse the strings. While you attach the strings back to the violin, make sure that even the pegs are arranged in the reverse order (so that the E string peg does not get in your way while playing). You might need to change the size of the holes into which the pegs are inserted. A sandpaper or a file will do the trick. You can reverse the bridge too. (The hardest of them all) Change the position of the sound post to the opposite side. While putting everything back together, make sure that the position of the bridge is correct because it can make all the difference in the sound.The good news is that you can do everything at home by yourself. You can watch a couple of videos online that detail the process more clearly if you feel the need.