The Girl with the Dragon Tatoo

I was watching this amazing movie- The girl with the dragon tattoo when I noticed something funny that I cant figure out. It was a foreign language film (for me that is :D) with subtitles. At the peek when I was totally engrossed into the film I did not find my self " reading " the sub-titles. Reading as in hearing my voice in my head talking the words out loudly.. :D but as soon as i discovered this I started doing that and couldnt stop.. and then without knowing it I was engrossed in the movie again. I felt it reminiscent to falling asleep.. :D I can never put my finger on that one moment when sleep suddenly comes.. :D