Difference between Short talk and Tall talk

short talk—a brief lecture or address:

• The Director said that he would like me to broadcast a short talk under my own name.

tall talk —(coll.) boastful or pretentious talk (also: big talk):

• Tall talk is luckily an object of suspicion to Englishmen.

Note: The expression does not correlate in meaning with the phrase talk highly—(also: speak highly) praise a person or thing:

• He talks very highly of his students and the faculty.