This paper investigates the perception of word prosodic contrasts as a function of focus and position in the intonational phrase in two Dutch Limburgian dialects, Roermond and Weert. While their word prosodic contrasts share a historical source, the two dialects differ in that Weert realizes the prosodic contrast by duration, while Roermond uses,f(0). In addition, the Roermond dialect, but not the Weert dialect, appears to neutralize the prosodic distinction outside the focus constituent in phrase-internal syllables. The stimulus materials were naturally elicited word pairs in which the prosodic contrast marks a difference in grammatical number. In two perception experiments, listeners decided in a forced-choice task whether the words represented a singular or a plural form. Listeners with a Roermond Dutch background recognized the members of the opposition in focused contexts and phrase-final contexts, but failed to do so in phrase-internal, nonfocused contexts. By contrast, listeners whose native language was Weert Dutch perceived the grammatical number distinction in all contexts with comparable measures of success. Second, the presentation of stimuli consisting of words excised from their sentences significantly impaired the recognition of grammatical number in the Roermond group, but not in the Weert group. These results suggest that the perception of the tonal contrast, but not that of the duration contrast, depends on the intonational context. The fact that in the Roermond dialect lexical and intonational tones are integrated in the same phonological grammar thus turns out to have significant consequences for the functionality of the word prosodic contrast which can be shown to be absent when this phonological contrast is encoded differently. (c) 2005 Elsevier Ltd. All rights reserved.