William Venator brought this word, meaning foolish babbling, back from oblivion in his self-published 2003 satire, Wither This Land, which told of political upheavals following the opposition by saboteurs to fox hunting in Britain:
The day had proceeded well at Stanthorpe but Downing Street was fuming. Cramp, caught unawares, had given an excellent stultiloquy, much to the press’s amusement, on the need for “action, containment for flaunting the law, overweening disapproval, community and tolerance needed.”
Was flaunting part of the satire or an authorial error, I wonder?
It’s a pity it’s so rare, as there are quite a number of current political figures to whom it could be applied (no names, no pack drill). The only other modern writer I know of who has used it is John Steinbeck. It appears in his fictional portrayal of the life of the buccaneer Henry Morgan, Cup of Gold (1929): “In all the mad incongruity, the turgid stultiloquy of life, I felt, at last, securely anchored to myself.”
You might instead prefer the even rarer stultiloquence, whose adjectival form is in Christopher Fry’s The Lady’s Not For Burning, in which Justice Tappercoom says “The whole thing’s a lot of amphigourious, stultiloquential fiddle-faddle.”
Both are from Latin stultiloquus, speaking foolishly, which come in turn from stultus, foolish, plus loquus, that speaks.