What does it mean by kennedy "improvised remarks "?

Explanation:

Improvise is like to give a speech without practicing your own speech, and remarks mean to mention or regard with attention. So as a example of  " Kennedy's improvised remarks" is when he made a statement of MLK's assassination at Indianapolis, Indiana, April 4, 1968  

the alfred thayer mahan award for literary achievement is awarded each year by the navy league of the united states. the award is named for an american naval historian and theorist, rear admiral alfred thayer mahan, united states navy who, through his writing, provided stimulus and guidance to those who share in the defense of the nation. presented since 1957, "this award for literary achievement is awarded to a u.s. navy officer, u.s. marine corps officer, enlisted service member, or civilian who has made a notable literary contribution that has advanced the knowledge of the importance of sea power in the united states."[1]