blather (v.)

Middle English bladdre, from Old English blædre (West Saxon), bledre (Anglian) "urinary bladder," also "blister, pimple," from Proto-Germanic *blodram "something inflated" (source also of Old Norse blaðra, Old Saxon bladara, Old High German blattara, German Blatter, Dutch blaar), from PIE root *bhle- "to blow." The extended senses date from early 13c., from animal bladders being used for buoyancy, storage, etc.

bhlē-, Proto-Indo-European root meaning "to blow," possibly a variant of PIE root *bhel- (2) "to blow, swell."

It forms all or part of: afflatus; bladder; blase; blast; blather; blaze (v.2) "make public;" blow (v.1) "move air;" conflate; deflate; flageolet; flatulent; flatus; flavor; inflate; inflation; insufflation; isinglass; souffle.