Universal 669:

Original: Question particles may co-occur with inversion in yes-no questions.
Standardized: IF yes-no questions are marked by question particles, THEN they may in addition be marked by verb inversion, and vice versa.
Keywords: interrogative sentence, yes-no question, question particle, inversion
Domain: syntax
Type: mutual implication
Status: achronic
Quality: almost absolute?
Basis: 79 languages surveyed in Ultan 1978c
Source: Ultan 1978c: 232

Counterexamples: French, where the two devices are mutually exclusive in yes-no questions (Ultan 1978c: 232).

FP