Cf: Foolish tongues talk by the dozen (Am.). Fools cannot hold their tongues (Am.). Many speak much who cannot speak well (Am.). The shallowest persons are the most loquacious (Am.). They talk most who have least to say (Am.). The tongue of idle persons is never idle (Br.)
Русско-английский словарь пословиц и поговорок. Академик.ру. 2013.