We examined whether a bilingual advantage can be found in older bilinguals that share the same cultural background with monolinguals. Sixteen Gaelic-English bilinguals over the age of 60 years were compared with three monolingual control groups in performance on the Simon task, as well as in general intelligence and socio-economic status. Some of the monolinguals were bidialectal allowing us to also test whether switching between dialects can incur similar cognitive benefits as bilingualism. Results showed no group differences in overall reaction times as well as in the Simon effect suggesting that individuals that share a cultural background may not exhibit differences in inhibitory control even if they routinely use another dialect or another language. This opens up the possibility that other factors associated with bilingualism, like immigrant status, may be responsible for the bilingual advantage found in some but not in other studies.