Our study examines the extent to which Afrikaans-Spanish bilingual speakers show L1-L2 interactions in the rhythmic properties of their two languages. Eight Afrikaans-Spanish bilingual speakers who live in Patagonia, Argentina read aloud sentences in Afrikaans (their L1) and Spanish (their L2), and ten Afrikaans and eight Spanish monolingual control speakers read aloud sentences in their respective native languages. Measurements of consonantal and vocalic intervals were taken using Praat. Our results suggest that there are L2 to L1 transfer effects for vowel metrics but not for consonant metrics. We argue that this difference derives from the fact that Afrikaans phonology controls vowel duration, whereas neither Spanish nor Afrikaans use phonemic consonant length. This shows that the extent of rhythmic influence between languages can depend on segment-specific aspects of the two phonological grammars under study.