thumb|right|240px|[[William-Adolphe Bouguereau, The Difficult Lesson (1884)]]
Hyperlexia is a syndrome characterized by a child's precocious ability to read. It was initially identified by Norman E. Silberberg and Margaret C. Silberberg (1967), who defined it as the precocious ability to read words without prior training in learning to read, typically before the age of five. They indicated that children with hyperlexia have a significantly higher word-decoding ability than their reading comprehension levels. Children with hyperlexia also present with an intense fascination for written material at a very early age.
Hyperlexic children are characterized by word-reading ability well above what would be expected given their age. First named and scientifically described in 1967, it can be viewed as an ability in which word recognition ability goes far above expected levels of skill. Some hyperlexics, however, have trouble understanding speech. Between five and twenty percent of autistic children have been estimated to be hyperlexic.
Hyperlexic children are often fascinated by letters or numbers. They are extremely good at decoding language and thus often become very early readers. Some English-speaking hyperlexic children learn to spell long words (such as elephant) before they are two years old and learn to read whole sentences before they turn three.
Etymology
The word hyperlexia is derived from the Greek terms and .
Development
Although hyperlexic children usually learn to read in a non-communicative way, several studies have shown that they can acquire reading comprehension and communicative language after the onset of hyperlexia.
Types of hyperlexia
In one paper, Darold Treffert proposes three types of hyperlexia. These are:
- Type 1: Hyperlexia marked by an accompanying language disorder.
- Type 2: Hyperlexia marked by an accompanying visual-spatial learning disorder.
Non-English studies
In studies in Cantonese and Korean, subjects were able to read non-words in their native orthography without a delay relative to the speed with which they read real words in their native orthography. There is a delay noted with exception words in English, including the examples chaos, unique, and enough. These studies also illustrate difficulties in understanding what it is that they are reading. The findings suggest that non-hyperlexic readers rely more heavily on word semantics in order to make inferences about word meaning.
The Cantonese study distinguish homographs and determine the readings for rarely used characters. In this study, the subject also made errors of phonetic analogy and regularization of sound. The authors of the study suggest that the two-routes model for reading Chinese characters may be in effect for hyperlexics. The two-routes model describes understanding of Chinese characters in a purely phonetic sense and the understanding of Chinese characters in a semantic sense.
Comprehension difficulties can also be a result of hyperlexia. Semantics and comprehension both have ties to meaning. Semantics relates to the meaning of a certain word while comprehension is the understanding of a longer text. In both studies, interpretation-based and meaning-based tests proved difficult for the hyperlexic subjects. In the Weeks study, the subject was unable to identify characters based on the logographic aspect of the writing system, and in the Lee and Hwang study, priming was ineffective in decreasing reading times for hyperlexics.