You may have already noticed that sometimes your yarn gets untwisted or overly twisted while knitting it. If you have ever practiced the "long tail cast-on" technique, you have observed this phenomenon! There are several reasons why yarn splits or gets over-spun.
The most common problem is the nature of the yarn itself. Most yarns comprise individual strands of fiber twisted together to form a thread. These twists can be more or less tightly wound, depending on the brand or type of yarn.
When knitting and turning your work consistently to the same side, either because you are at the end of a row or knitting in the round, you can increase (or decrease) the torsion of your yarn.
This phenomenon is normal and unavoidable, but you can try the following tips to minimize it: Use the end of the yarn from the outside of the ball, turn your work alternately clockwise and counterclockwise, and keep your yarn a bit further away from you while you knit!
Ultimately, you can substitute for another yarn to knit your pattern