50 year anniversary of JFK's "Ask Not" inauguration speech

Did JFK use the motto of his high school in his inauguration speech 50 years ago?

Thurston Clarke wrote a book called, “Ask Not: The Inauguration of John F. Kennedy and the Speech That Changed America.”

Mr. Clarke wrote later that "important and heretofore overlooked documentary evidence" proves that Kennedy was "the author of the most immortal and poetic passages of his inaugural address," including the famous line that gives the book its title, "Ask not what your country can do for you - ask what you can do for your country."

The photo above shows President John F. Kennedy delivering his inaugural address in 1961, whose memorable phrases are still the subject of conjecture.

John F. Kennedy graduated from Choate Rosemary Hall, a private high school in Wallingford, Connecticut.

From the second paragraph at the first link below:

John F. Kennedy was a 1935 graduate of the Choate school (who, incidentally, graduated 64th in a class of 112), was so inspired by Choate's motto, "Ask not what your school can do for you-- but what you can do for your school." that he paraphrased it in his eloquent inaugural address as: "Ask not what your country can do for you -- but what you can do for your country.”

Did Kennedy write the inauguration speech? Many think he had input into a speech that was prepared by Ted Sorensen.

The “Ask Not” part of the speech would have been added by Kennedy because Sorensen, who was from Lincoln Nebraska, likely would not have been aware of the Choate school motto.

Mr. Clarke insists that Kennedy was the main architect of the speech and the “ask not” words were his even though Ted Sorensen was not only Kennedy’s legal aid but was his chief speechwriter.

Does Mr. Clarke’s book have the definitive answer or, as reported above, are the memorable phrases still the subject of conjecture?

Link here and here.