Try putting your DVD in your PC.
If you have a DVD reader see if you can get subtitles out of it, so you can eliminate the media being the problem.
This way if you know you can get subtitles on the PC, then you will know the problem is with the DVD player.
If you're on the 2k/XP/Vista/w7 OS variant, you'll need a playback program like KMPlayer(personal preference), BSPlayer, VLC player, plenty others that are free.
One thing I can think of is, for certain CD's especially, bootlegs.. it may be that the DVD's from another region and you have to cycle through the subtitle options till it works. I know it's a dumb response, but did you try cycling through every subtitle option available on your dvd player/TV to see if it works?
Cleaning the head (eye) of the player is quite simple. You just try your best at attempting to remove any dust particles you think may be on it.
The little lens next to the spindle "holder" is your target. Your mission is to clean it using non-scratching methods the best you can.
Instead of writing it out how to do it, being lazy — I just googled it for you instead:
How to Clean the Laser Pickup Lens on your DVD Player | eHow.com
But usually this is reserved for issues where the disc isn't reading at all, or giving choppy playback issues.
Your mileage may vary.