Hyperlexia is a condition in which the main characteristics are an above normal ability to read accompanied with a below normal ability to understand spoken language. The symptoms are closely related to those of autism and some consider it to be an autism spectrum disorder whereas others contest it to be a completely different condition.

Hyperlexia appears to be different from what is known as hypergraphia, the urge or compulsion to write, although as with many mental conditions or quirks it is possible that this is more a matter of opinion than strict science. Often, hyperlexic children will have a precocious ability to read but will learn to speak only by rote and heavy repetition, and may also have difficulty learning the rules of language from examples or from trial and error, which may result in social problems.

Children with hyperlexia may recite the alphabet as early as 18 months, and have the ability to read words by age two and sentences by age three. Many are overly fascinated with books, letters, and numbers. Often their ability is looked at in a positive light, so many parents delay their children receiving help because they believe that their child may be a struggling genius.

Hyperlexia often coexists with high functioning autism or Asperger syndrome. Hyperlexia is not seen as a separate diagnosis; however, with current fMRI research revealing that hyperlexia affects the brain in a way completely opposite to that of dyslexia, a separate diagnosis may be on the horizon.

Despite hyperlexic children's precocious reading ability, they may struggle to communicate. Their language may develop in an autistic fashion using echolalia, often repeating words and sentences. Often, the child has a large vocabulary and can identify many objects and pictures, but cannot put their language skills to good use. Spontaneous language is lacking and their pragmatic speech is delayed. Hyperlexic children often struggle with Who? What? Where? Why? and How? questions. Between the ages of 4 and 5 many children make great strides in communicating and much previous stereotypical autistic behavior subsides.

Often, hyperlexic children have a good sense of humor and may laugh if a portion of a word is covered to reveal a new word. Many prefer toys with letter or number buttons.

They may have olfactory, tactile, and auditory sensory issues. Their diets may be picky, and often potty training can be difficult.

Social skills lag tremendously. Social stories are extremely helpful in developing effective age-relative social skills, and setting a good example is crucial.