In a study comparing executive functions among US Spanish-English bilinguals from low socio-economic (SES) backgrounds to monolinguals of each language, Grote et al. find that bilingual advantages already manifest themselves in pre-school children. This commentary recommends building on this finding, and further investigate the causes underlying the observed executive function (EF) modulations in child bilingualism. A closer investigation of bilingual children's dominance profiles and their bilingual practices, such as code-switching, may shed light on how bilingualism shapes the developmental trajectory of executive functions. The commentary also challenges the notion of 'monolingualism', and discusses whether bilingualism variables should be operationalised in a continuous or in a categorical manner. [For the article by Grote, Scott and Gilger, "Bilingual Advantages in Executive Functioning: Evidence from a Low-Income Sample," see EJ1315042.]