This article explores the role of transfer and Universal Grammar (UG) in second language (L2) phonology by investigating the L2 acquisition of stress/prominence in footless languages, such as Turkish and French, which have fixed word- and phrase-final prominence respectively. It is proposed that once the prosodic constituent Foot is projected in a footed first language (L1), such as English, it is impossible to expunge it from the grammar in learning a footless L2. Learners in this condition will, instead, be restricted to resetting parameters that act on the Foot (e.g. trochaic/iambic, iterative/non-iterative, weight-sensitive/weight-insensitive). In order to investigate these predictions, a semi-controlled production experiment was conducted with English- and French-speaking learners of L2 Turkish, of various proficiency levels. The results largely confirm our predictions. None of the English-speaking subjects were able to rid their grammar of the Foot. They were, however, able to make various UG-constrained changes to their grammar, such as resetting Extrametricality from Yes to No, and later, Foot-Type from Trochaic to Iambic, thereby having increasingly more word types with word-final (but footed) stress. French-speaking learners, on the other hand, produced target-like footless outputs from the beginning, with word-final prominence. The findings provide strong evidence for UG-based theories of L2 acquisition: (i) interlanguage grammars, even when non-targetlike, are 'possible' grammars, paralleling other natural languages, (ii) options ruled out by UG, such as weight-insensitive iambs, are not employed, despite such a stage being cognitively most reasonable, and (iii) grammar change is brought along on a parameter-by-parameter basis, instead of being reflective of frequency.