This study investigates whether excrescence is phonological epenthesis or articulatory overlap by investigating whether a prosodic domain boundary intervening between the nasal and the fricative affects insertion. Articulatory overlap effects are expected to remain constant across the board, whereas phonological epenthesis is expected to be targeted for domain-final lengthening. The duration results are that neither excrescence nor underlying segments are affected by domain-final lengthening, but excrescent closure is significantly shorter than underlying closure. The short segments support an articulatory overlap hypothesis, but the lack of final lengthening opens up new questions for further research.