Goldrick, Putnam and Schwarz (henceforth Goldrick et al.) base their computational account of code mixing on two premises, (1) that code mixing is subject to grammatical principles and (2) that “mental representations in bilingual speakers incorporate blends of structures from each language”. While there is copious evidence for the first premise, the second is far less well empirically supported. The authors imply that the second premise, the assumption of blend representations, is supported by Kroll & Gollan's (2014) review of speech planning in two languages, but this is not the case. Kroll & Gollan (2014:1) do indeed discuss evidence for the “parallel activation of the bilingual's two languages” but in terms of competition between alternatives rather than blended representations. The notion of blend is of course familiar to code-switching researchers from work on bimodal bilingual code mixing, as Goldrick et al. acknowledge, but here the term refers to “simultaneously produced English words and ASL signs” (Emmorey, Borinstein, Thompson & Gollan, 2008: 43).