Speech rhythm is understood as a byproduct of phonetic and phonological characteristics like syllabic structure, vowel reduction and the role of accent. In order to capture these properties, several rhythm metrics have been proposed in the literature so as to give an account of different aspects of rhythm. The aim of this study is to focus on the role of accent, as manifested in the prominences of an utterance, in the timing patterns of two typologically different rhythms represented by Spanish and English. Two rhythm metrics, %V and VarcoV, have been chosen in order to measure the production of a specially designed reading task by speakers from Patagonia, south of Argentina, as well as the southeast of England and the northeast of the United States. Results indicate that (1) there is a significant effect of prominences in the two English varieties, but not in Spanish, as shown by %V and VarcoV, and (2) there is a categorical difference between rhythm types, as shown by VarcoV.