"Praticamente" is an interjection. It is probably one of the most vague and weasel words used in colloqual speech, I think in particular by Romans, maybe by people from Center-Italy. The closest words in English are: "basically", or "well", "so", "you know". It is used, I would say to express the fact that the person is thinking about, pondering, or that intends to clarify somthing, to point out or start a little explanation.
It can have 100 "meanings" and has none; it is merely a colloqual word, it won't be allowed in a written statement. Its use is associated with people who talk imprecisely, ("basically", "well" , "so"...) sometimes I meet Romans who use a ton of "praticamente" without any necessity, and that doesn't sound particularly a good thing to me. This word occurred frequently also in some other testimonies by other witnesses and irritated one Italian translator from Rome, who pointed out that it was not a beautiful way of speaking.