"Watch TV and video online in the language you're learning. You may not understand much of it but it will help you get used to how the language sounds and, with the help of the visuals, you'll pick up odd words and phrases."
More: BBC - Learn a language? Why? Which? How?
When we want to refer to TV and video in general, should we use the definite article the before the word visuals? Can I say, please watch visuals in your free time instead of turning your neighbors against each other?
The piece if specifically talking about the visuals in the TV and video programs you are watching in the language you're learning. As far as your suggested sentence is concerned, I cannot begin to imagine what watching visuals has to do with turning your neighbours against each other, so my answer is "No, you cannot say that". Obviously, those words could come out of your mouth so, physically, you can say it, but it means nothing so please don't say it.
