Code-switching — alternating between languages or dialects within a conversation — is not a sign of deficiency. It is a sophisticated communicative skill that monolingual speakers cannot perform.
The switch carries meaning: it can signal intimacy, mark a topic shift, invoke a community, or create ironic distance. Bilingual speakers code-switch strategically, even if unconsciously.
The deficit framing ("they can't commit to one language") misreads pragmatic competence as grammatical failure. This is a common error in language policy.