#0.5: Tennis shoes is more of a regional term, which is why it’s .5 rather than a whole number, but unless you bought your shoes specially to play tennis, they’re called sneakers not tennis shoes.
#3: Conversate is not a word. You can converse or have a conversation, but you can’t conversate.
#2: Worser. You can make something worse (more bad than it already was) or something can be the worst (the most bad), but not worser.
#1: Irregardless is not a real thing. Regardless is already negative. So, adding a negative prefix like ir no longer communicates a negative word. Just like in math, two negatives make a positive. Adding the negative prefix ir to an already negative word regardless makes no sense. Try irrespective or just plain regardless instead.
Remember, irregardless of who you conversate with, using these words is going to make you look way worser than your friends. If that statement sounded completely okay to you, go ahead and put on your tennis shoes and review this post again.