No, they are not. But they are not fixed as objective like say gravity.
So here is an example of 2 languages; Linear A and B.
Linear A and Linear B | script We can only read one of them for its meaning.
The explanation is that the meaning of words as words is inter-subjective. I.e. you can't see the meaning, you understand it because you have learned that as a child through the psychological processes of mimicking behavior until becomes internalized as understanding.
Now that means that for all humans capable of learning that and actually undergoing the process, it is a process in time, over time in a culture, where they learn words including those who reflect the value system of that culture.
That is the basis. Do you have any questions so far?