STUMPERS CXCVII

Can you think of a common five-word expression that means TONGUE TIED that is make up of a one-letter word, a two-letter word, a three-letter word, a four-letter word, and a five-letter word - although not in that order?

HINT:
Here are the words in order:
_ _   _   _ _ _ _   _ _ _    _ _ _ _ _

Answer:

AT A LOSS FOR WORDS 

Credit:
NPR Weekend Edition Sunday Puzzle
March 15, 2009
Will Shortz