Exclamatory

“How beautiful speech is!”
Is the above sentence correct?
another question,

  1. If I were a king.
  2. Were I a king.
    Are the meaning of the above two sentences same.

“How beautiful speech is!” Is the above sentence correct?-- Yes

  1. If I were a king.2. Were I a king. Are the meaning of the above two sentences same.-- Yes

“How beautiful speech it is!”
Is this correct?

No. Your choices are:

How beautiful speech (= speaking) is! (Speech is beautiful)
What a beautiful speech (= an oral presentation) it is! (The speech is beautiful.)
How lovely you are! (You are lovely.)
What a lovely girl you are! (You are a lovely girl.)