[leonid]

One thing I forgot, Every word we know is a symbol.. When we read, we just look at the word shape. We can sound the words out because we know what each individual letter should sound like because we memorized those letters as symbols.
The only things we know to be true are what our body tells us.. And even sometimes, it can go whacky (nerve problems, etc..). Thanks to our sensory organs and electromagnetic energy (light)/mass (pressed wood fibers and black ink in a book) sound propagation, braille, et.. we can convey information to other people in many different ways

There have been quite a few feral children found in remote areas that live with animals and no know language. I don't know about you, but when I think in my head, I am talking in English! I cannot imagine a thought without language, can you? These feral children think things like "I need food" or "I'm tired" because all they know is what their body is telling them. They can't make logical deductions because formal logic is mediated through language. When programmers write programs, they think of logical structuring in English and sometimes even think in the programming language they're using (with English words of course!).. Just something to think about :)

[wideminded]

I don't know about you, but when I think in my head, I am talking in English!

Even with you, I'm sure there are exceptions to this rule.

I cannot imagine a thought without language, can you?

Yes.

These feral children think things like "I need food" or "I'm tired" because all they know is what their body is telling them. They can't make logical deductions because formal logic is mediated through language.

Language is not required to make logical deductions or even to use formal logic. Even animals make some logical deductions. A feral child of sufficient age who is hungry is still likely to be able to make some logical plans on how to obtain food.