Thread: "do" in Present Simple

You do use auxilary verb "do" in affirmative sentences very often. Why do you do that? I was taught that there is nothing auxilary verb in Present Simple affirmative.

In many languages, do is implied- however English is not one of those.
A good example is Spanish.
[i]

It is just an indicator of emphasis. e.g. "you should learn to speak russian! -- but I do speak Russian."
when i just started studying english i had a book which explained this (and a few other very intuitive but not found in Russian things, like article use, verbs with particle modifiers, etc) really well. i do not remember its name now and i do not have it around any more (i really should find out though; it was printed at some point in early 90's and had a rather poor quality white paper cover with the title in multicolor print and with some other colorful pictures of airplanes boats and such; looked kinda cheezy but it was very good).