Can speech/language impairment be greatly improved/reversed?

Not usually reversed: But often treated do do not give up!

Specific language : impairment is a delay in mastering language in a child with no hearing loss or neurodevelopmental disorder. SLI includes deficits in vocabulary, syntax, grammar, phonological awareness & conversational skills, but not articulation. There is often a family history of SLI. The risk of dyslexia is 40-70%. Early, intensive language therapy & a language-enriched home environment help minimize impact.