Question-word questions in Czech lexically mark their interrogative function in the initial position: in their standard form, they begin with an interrogative lexeme. For many linguists, this is a sufficient reason for resigning on intonation marking, so they claim that the speech melody in these questions is identical to the melody of statements.
A careful observation of the current Czech speech suggests otherwise. This paper presents a perceptual experiment in which Czech speakers evaluated two contrastive forms of the interrogative melody, specifically the one with a late peak modelled after statements (as suggested by some authors), and the one with an early peak modelled after our empirical data collected previously.
Thirty-two listeners expressed a statistically significant preference for the early peak in a perception test. This outcome resonates with the sample of speech production of the questions.
However, the late peak is also possible and acceptable: we assume that it might be a signal of contrastive emphasis or an implicational cue.