Several other languages don't bother with multiple types of present tense. In German, for instance, Ich gehe means both "I go" and "I am going."
Now, Farsi takes it one step further. Present tense verb conjugation can also be construed as future tense. For instance, miravam means "I go," "I am going," and "I will go."
My mom occasionally uses this Farsi grammar rule in spoken English. For instance, she will say things like, "Give me his number, I call him" instead of "Give me his number, I will call him." Having heard such phrasing all my life, it doesn't sound all that weird to me, and I can tell when she's using present tense versus when she means for something to be future tense. In fact, I sometimes do the same thing with my spoken English, though I'm far more likely to substitute present for future tense if a) I'm speaking to my mom or b) I've just recently spoken with her.
I have always been cognizant of this, but it wasn't until now- getting into the Farsi grammar rules for present/future tense- that I've understood the reasoning for it. My neat little revelation for the day. =)