Here is a nice fact sheet from the NIDCD (National Institute on Deafness and Other Communication Disorders) on Specific Language Impairment to use and or file in your toolkit!
Image Credit:  NIDCD

What is specific language impairment?
Specific language impairment (SLI) is a language disorder that delays the mastery of language skills in children who have no hearing loss or other developmental delays. SLI is also called developmental language disorder, language delay, or developmental dysphasia. It is one of the most common childhood learning disabilities, affecting approximately 7 to 8 percent of children in kindergarten. The impact of SLI persists into adulthood.
What causes specific language impairment?
The cause of SLI is unknown, but recent discoveries suggest it has a strong genetic link. Children with SLI are more likely than those without SLI to have parents and siblings who also have had difficulties and delays in speaking. In fact, 50 to 70 percent of children with SLI have at least one other family member with the disorder.
Read the Rest of this Fact sheet on the NIDCD Website