How do autism and down syndrome affect language development?

From infancy through: adulthood people with DS have delays in receptive & expressive language, ='in some areas to cognition, usually mild-moderate Intellectual Disability, others lower..Babies, toddlers & children with Autistic Spectrum Disorder may not talk or may have bizarre jargon mixed with babbling, then words, but they lack joint attention, communicative intent & reciprocal conversational skills.