What are difficulties in social interaction and social communication?
Since autistics process information slightly differently to non-autistics, the two don’t automatically get into synch when communicating. It’s like autistics need to learn a second language to communicate with non-autistics. And, like anyone speaking a newly-acquired second language, autistic individuals may miss things like subtleties, allusions, idioms, and the way that things like tone and body language can modify a message, that others take for granted. This often leads to awkwardness, misunderstandings, and withdrawal.
Many autistics report they find it easier to communicate with other autistics, since neuro-typicals tend to just ‘get’ various things, but since autistics are individuals, that doesn’t mean that such communication is always harmonious.
Since non-autistics constitute a majority of the population, most autistics have to communicate with non-autistics most of the time, so their challenges when doing so are one of the defining aspects of autism.