This study examines whether proficient second language speakers of Belfast English and Northern Standard German accommodate on cross-linguistically different intonational phonological categories and their gradient phonetic implementation in a collaborative map task. Belfast English and Northern Standard German select two different intonation patterns for nuclear pitch accents in declarative utterances. Northern Standard German features a falling pitch accent pattern. In Belfast English, a rising intonation contour is realised. The experiment investigates the production of phonologically different pitch accents in declarative utterances, gradient acoustic characteristics of pitch range in utterance-final position and peak alignment in nuclear pitch accents. Evidence was found for accommodation for all three prosodic phenomena. However, the accommodation patterns were asymmetric in the Belfast English and the Northern Standard German groups of speakers. Furthermore, both phonologically contrastive characteristics and gradient phonetic acoustic detail appeared to be influenced by factors of linguistic function, perceptual salience and familiarity.