When speaking a foreign language (L2), non-native speakers’ (NNS) speech contains some variable degree of foreign accent (FA) that is perceivable by the native speakers (NS) of that language based on the production of phonetic gestures characteristic of their mother tongue (L1), and that differ from those of the foreign language (L2) in terms of the segmental (vowels and consonants) and prosodic (stress, rhythm and intonation) features. Causes such as neuro-plasticity and length of residence, for example, are claimed to interfere in L2 production. This work aims to analyze how L2 speech rhythm of English is produced by Brazilian Portuguese (BP) speakers and how prosodic variables such as, metric and acoustic correlates, influence FA. This research is based on Barbosa (2006) for the dynamic determination of speech rhythm in addition to Ramus et. al. (1999) and so, on the choice of metrics and segmentation procedures. As for the methods of analysis, phonetic data from twenty BP and four American speakers were collected. Next, the data were segmented into different unit procedures for the purpose of carrying out acoustic and statistical analysis. Results pointed out to a significant difference between L1 and L2 rhythms.