Is there any difference in
1) He is not educated
2) He is uneducated ?
And if there is no, is it possible to make negation with other words by putting "not" in front of them?
If you have different negation prefixes (un, mis, dis etc.) and every word has its own own, for example
"Understand" can have only "mis" (if I am not mistaken).
I was misunderstood
But if I am not sure which prefix I have to use with, for example, "understand" can I just put "not" before it to have the same sense?
I was not understood
The same with "not educated" and "uneducated"
Best Answer
Regarding misunderstood vs not understand, I would take it that misunderstood means the listener thought that they understood what was said, but had perhaps acted slightly differently based on their interpretation.
On the other hand, not understand would mean they didn't understand anything that was said.
For example:
Joe misunderstood when I asked him to parboil the potatoes, instead he boiled them for far too long.
vs
Joe did not understand when I asked him to parboil the potatoes; he had to look up the definition online.
With your two options - he is not educated and he is uneducated - and without any further context, they mean the same thing. However, depending on the context, you might use one or the other.
So to answer your question, no, using the different prefixes mentioned in your question might not always have the exact same meaning.