From Battos (a proverbial stammerer) and logos; to stutter, i.e. (by implication) to prate tediously -- use vain repetitions.
see GREEK logos
a. to stammer, and, since stammerers are accustomed to repeat the same sounds,
b. to repeat the same things over and over, to use many and idle words, to babble, prate; so Matthew 6:7, where it is explained by ἐν τῇ πολυλογία, (Vulg.multumloqui; (A. V. to use vain repetitions)); cf. Tholuck at the passage Some suppose the word to be derived from Battus, a king of Cyrene, who is said to have stuttered (Herodotus 4, 155); others from Battus, an author of tedious and wordy poems; but comparing βατταρίζειν, which has the same meaning, and βάρβαρος (which see), it seems fax more probable that the word is onomatopoetic. (Simplicius, in Epictetus (ench. 30 at the end), p. 340, Schweigh edition.)