*bhā-; Proto-Indo-European root meaning "to speak, tell, say."

It forms all or part of: abandon; affable; anthem; antiphon; aphasia; aphonia; aphonic; apophasis; apophatic; ban (n.1) "proclamation or edict;" ban (v.); banal; bandit; banish; banlieue; banns (n.); bifarious; blame; blaspheme; blasphemy; boon (n.); cacophony; confess; contraband; defame; dysphemism; euphemism; euphony; fable; fabulous; fado; fairy; fame; famous; fandango; fatal; fate; fateful; fatuous; fay; gramophone; heterophemy; homophone; ineffable; infamous; infamy; infant; infantile; infantry; mauvais; megaphone; microphone; monophonic; nefandous; nefarious; phatic; -phone; phone (n.2) "elementary sound of a spoken language;" phoneme; phonetic; phonic; phonics; phono-; pheme; -phemia; Polyphemus; polyphony; preface; profess; profession; professional; professor; prophecy; prophet; prophetic; quadraphonic; symphony; telephone; xylophone.

It is the hypothetical source of/evidence for its existence is provided by: Greek pheme "speech, voice, utterance, a speaking, talk," phōnē "voice, sound" of a human or animal, also "tone, voice, pronunciation, speech," phanai "to speak;" Sanskrit bhanati "speaks;" Latin fari "to say," fabula "narrative, account, tale, story," fama "talk, rumor, report; reputation, public opinion; renown, reputation;" Armenian ban, bay "word, term;" Old Church Slavonic bajati "to talk, tell;" Old English boian "to boast," ben "prayer, request;" Old Irish bann "law."

1640s, from French fatuité (14c.), from Latin fatuitatem (nominative fatuitas) "foolishness, folly," from fatuus "foolish, insipid" (see fatuous).

"will o' the wisp, jack-o-lantern," 1560s, Medieval Latin, literally "foolish fire;" see igneous + fatuous. "It seems to have been formerly a common phenomenon; but is now exceedingly rare" [OED].

1530s, "turn (something) to foolishness, frustrate by making foolish," from Latin infatuatus, past participle of infatuare "make a fool of," from in- "in" (from PIE root *en "in") + fatuus "foolish" (see fatuous). Specific sense of "inspire (in someone) a foolish passion beyond control of reason" is from 1620s. Related: Infatuated; infatuating.

An infatuated person is so possessed by a misleading idea or passion that his thoughts and conduct are controlled by it and turned into folly. [Century Dictionary]