After some remarks on the parallel cognitive structure of language and music, the rhythmic organization of speech is discussed with special attention to the phonetic notion of timing. Following the quantitative metric already adopted in the analysis of speech and musical compositions, the results of a study on a set of Italian and English popular songs are presented. the results confirm the polarity between syllable timing and stress timing. At the same time, we argue that quantitative models are not enough to grasp the essence of the linguistic rhythm, since structural phonological information is also required.