As first observed by Ladd in 1981, English polar questions with high negation (e.g., Aren't they adding a menu item?) can be used both to check the speaker's belief that the proposition p is true (e.g., p = they are adding a menu item) and to check the addressee's belief that p is not true (¬p). We hypothesized that this ambiguity can be disambiguated prosodically. We further hypothesized that the prosodic disambiguation is absent in German, because the checked proposition can be marked morpho-syntactically, with questions with high negation checking p and low negation questions (e.g., Are they not adding a menu item?) checking ¬p.A production study tested these hypotheses with 24 speakers of Western Canadian English and German each (764 and 767 total utterances, respectively). The results showed that, when the speaker originally believed p and the addressee implied ¬p, English speakers preferred questions with high negation over low negation questions, confirming Ladd's observation, and used intonation to mark whose proposition they were checking, as hypothesized. By contrast, German speakers marked this distinction morpho-syntactically, realizing mostly questions with high negation to check their own proposition and low negation questions to check the addressee's proposition. Their prosody, in turn, was largely determined by the morpho-syntactic question form. The study further manipulated the speaker's certainty of the checked proposition, but, in contrast to studies on Romance languages, found that certainty itself was not marked.
Keywords: Ladd’s ambiguity; Yes-no question; bias; speaker certainty.