Take a look at this really nice piece from Scott Prath, MA, CCC-SLP in the ASHA Leader, about identify delay vs disorder in bilingual kids. A strong background in understanding bilingualism is critical for monolingual and bilingual SLPs alike.
“Bilingual development is incredibly complex. It varies by languages involved, age of acquisition, settings where the student uses each language and many other factors. Any perusal of research on bilingualism would convince you of this complexity. However, there is a fairly simple, research-based way to get a sense of whether a child experiences true communication issues or just needs to adjust to a new language…”
Source: The ASHA Leader, November 2016, Vol. 21, 32-33. doi:10.1044/leader.SCM.21112016.32