Electropalatographic data for the alveolar nasal, the alveolar tap and clear /l/ in two Catalan dialects reveal that all three consonants undergo continuous closure fronting after low and back rounded vowels in VCV sequences, next to these same vowels in postpausal and prepausal position, and next to labial and velar consonants in consonant clusters. It is argued that this flapping mechanism is associated with the low degree of tongue constraint involved in the production of the three alveolars.