The paper deals with perceived speech rhythm, starting from the observation that two nouns with a conjunction in between ('X and/or Y', cf. title) sound more rhythmical in a particular noun order. A perception experiment on German with real and pseudo nouns provides evidence that speech rhythm is not just created prosodically by means of high and low or long and short syllables, but that the phonetic properties of the vowel nuclei and of the consonantal onsets and offsets of the stressed syllables are separate segmental constituents of speech rhythm.