When we read it in the Greek we find that the word battalogeo has nothing to do with "repetition," vain or otherwise, and was mistranslated by the KJV translators.
Not that is an interesting assertion and one that I have not heard before. Allow me some time for research.
[945]
1) to stammer
2) to repeat the same things over and over, to use many idle words, to babble, prate. Some suppose the word derived from Battus, a king of Cyrene, who is said to have stuttered; others from Battus, an author of tedious and wordy poems.
Do you have some other translation?