Originally Posted by Dany
There should be a comma after "however".
I learned French easily. However, I didn't like my teacher.
With "however", a semicolon can be used to keep both clauses as one sentence.
I learned French easily; however, I didn't like my teacher.
I think they're really the same. I can say that "but" sounds more ordinary, whereas "however" sounds more like writing. It has just a bit more of a formal edge to it. However, that doesn't mean it's used only in formal language and writing. It's a regular word.
Student or Learner