This advanced reading ability is in contrast with difficulties understanding spoken language. Unlike other children, hyperlexic children don't learn language in the typical language learning progression of sounds to words to sentences, nor do they begin to develop a vocabulary starting with nouns, adding verbs and do on. Instead hyperlexic children memorize phrases, sentences or entire conversations. To express an idea, the children must be able to dissect what they have memorized to create original expressions.
Hyperlexic children have excellent visual and auditory memories, which means they easily remember what they see and hear. They use their memory to help them learn language. They will often exhibit echolalia, which is the repetition of phrases and sentences without understanding the meaning.
Given their difficulty with spoken language, hyperlexic children rarely initiate conversations.
Hyperlexia is considered to be part of the autism spectrum of disorders and like autistic children, children with hyperlexia have problems socializing and behaving appropriately. They also exhibit other characteristics of autism:
- Self-stimulatory behavior
- Ritualistic behavior
- Concrete and literally thinking
- Difficulty with abstract concepts
- Normal development until 18-24 months, followed by regression
- Need to keep routines
- Difficulty transitioning from one activity to another
- Sensitivity to sounds, smells, and touch
- Unusual fears
- Selective listening (may appear to be deaf)