I was once told de was the most common word in Portuguese. It seems to be true.
I was wondering the same. In English, it is very common to say "I can see you" or "I can hear you." Is the parallel construction less common in Portuguese? In other words, is it more common just to say "Eu vejo"
Not at all. Same frequency, I would say, in both languages. It just would be expressed with «posso» or «consigo», as Dr.Fandey said before. I have been speaking Portuguese since forever (my first language) and English since kindergarten, so I would say it is quite common in both. If I were playing peek-a-boo with a baby I would say, "I see you" or «Vejo-te.». If I were calling my friend on the phone when I see him on the bus and he has not noticed me yet, I could say either "I see you" (to sound humorously creepy) «Eu te vejo.» or "I can see you"/«Posso ver-te.».
I believe that Portuguese is the same as the other Romance languages in this respect: they rarely add "can" to verbs of perception. It is, by contrast, almost obligatory in standard English.
Can see (or can hear) are different. I see, or I hear means that is actually what you are doing while adding "can" means it is a possibility but may not actually be happening. I can put these pants on, or I can get back in bed and skip work. Just because I can, does not mean I will.
This sentence makes me think the guy gets arrested right after saying it.