is these sentences all correct?
He is Great. Great is He. Great He is.
If correct, how do they differ?
is these sentences all correct?
He is Great. Great is He. Great He is.
If correct, how do they differ?
For almost all situations, "he is great" is the correct form. The same goes for "she is beautiful" and "the night was cold." In most situations, the subject (he) comes before the verb (is).
The others are valid sentences, but they invert the positions of the subject and verb, which makes them sound unusual or maybe lyrical. You might expect to read them in a poem or another artistic work, like "Dark was the Night, Cold was the Ground," the blues song by Blind Willie Johnson.
Some subject-verb inversions sound more regular than others. But it's harder to go wrong with subject then verb, as in "he is great."
This is a form of emphasis. The term for it is anastrophe.
anastrophe n
reversal of the usual order of words for rhetorical effect.
This means we sometimes reverse or alter the normal order of words to make them stand out. We want what we say to be noted and remembered.
If someone says
Out you go!
it is certainly more emphatic, even more dramatic, than simply saying
You go out!
See also this answer on EL&U.