Information from parents and teachers tells us a lot about a student’s overall development and pattern of strengths and weaknesses. Because dyslexia is genetically linked, a family history of dyslexia indicates that a student is more likely to have dyslexia. A history of delayed speech or language also puts a child at-risk for reading difficulties. It is important to know the types and length of time of any interventions the student has received at school, home, or through tutoring, as well as the student’s response to the intervention. School attendance problems should be ruled out. A history of poor attendance, alone, can explain an identified weakness in skill development.

Until recently, an intelligence test was considered to be a necessary part of the evaluation because the diagnosis of a learning disability was based on finding a significant difference between IQ and reading skill. Poor achievement despite average or better intelligence was considered a key indicator. Current regulations no longer require that such a discrepancy be present when making a diagnosis. This change in the regulations came about because many studies have shown that intelligence is not the best predictor of how easily a student will develop written language (reading and spelling) skills. Instead, oral language abilities (listening and speaking) are considered the best predictors of reading and spelling. A formal measure of intelligence is not always needed to document average intellectual abilities. For younger children, parent information about language development and teacher information about the child’s ability to learn orally may indicate average intellectual abilities. For older students or adults, past achievement in school or work may indicate at least average intelligence.

Oral language, simply stated, refers to our ability to listen to and understand speech as well as to express our thoughts through speech. Oral language is made up of low-level skills, such as recognizing and making the sounds within our speech, and higher-level skills, such as getting meaning by listening to someone speak or creating sentences to express thoughts. Students with dyslexia typically have adequate higher-level language skills. Indicators of higher-level oral language skills include being able to understand an age-appropriate story and spoken directions, to carry on a conversation, and to understand and use words that are age appropriate. If a student has average higher-level oral language skills but much difficulty developing written language (reading and spelling) skills, the need for evaluation for dyslexia is recommended.
Although students with dyslexia usually have strong higher-level language skills, they typically have problems (a deficit) in low-level language skills (see following section “Phonological processing”). This deficit limits the ability to learn to read and spell using the sounds of the language. Young children with dyslexia often have delays in language development, but their higher-level language skills are usually age-appropriate by the time they enter school. Difficulties with higher-level language skills suggest a need for a language evaluation by a speech-language pathologist to rule out language impairment.

Word recognition is the ability to read single printed words. It is also called word reading or word identification. Tests of word recognition require that students read individual words printed in a list. The student is not able to use cues, such as the meaning of a sentence, to help them figure out the word. Tests of word recognition that score both accuracy and the time it takes for the student to read the words (fluency) are particularly useful. Students with dyslexia often become accurate but are still very slow when reading words. Both accuracy and the speed of word reading can affect understanding what is read.

Decoding is the ability to read unfamiliar words by using letter-sound knowledge, spelling patterns and chunking the word into smaller parts, such as syllables. Decoding is also called “word attack”. Decoding tests should use nonsense words (words that look like real words but have no meaning, such as frut or crin) to force the student to rely on these decoding skills rather than on memory for a word already learned.

Tests of spelling measure the student’s ability to spell individual words from memory using their knowledge of, for example, letter-sound pairings, patterns of letters that cluster together to spell one sound (igh in high; oa in boat), the way plurals may be spelled (s, es, ies) and so on. Spelling is the opposite of word attack but is even more difficult. It requires separating out the individual sounds in a spoken word, remembering the different ways each sound might be spelled, choosing one way, writing the letter(s) for that sound and doing the same, again, for the next sound in the word. Spelling stresses a child’s short and long-term memory and is complicated by the ease or difficulty the child has in writing the letters, legibly and in the proper order. Spelling is usually the most severe weakness among students with dyslexia and the most difficult to remedy.

Phonology is one small part of overall language ability. It is a low-level language skill in that it does not involve meaning. Phonology is the “sound system” of our language. Our spoken language is made up of words, word parts (such as syllables), and individual sounds (phonemes). We must be able to think about, remember, and correctly sequence the sounds in words in order to learn to link letters to sounds for reading and spelling. Good readers do this automatically without conscious effort. However, students with dyslexia have difficulty with identifying, pronouncing, or recalling sounds. Tests of phonological processing focus on these skills.

Students with dyslexia often have a slow speed of processing information (visual or auditory). Tasks measure Naming Speed (also called Rapid Automatic Naming). Sets of objects, colors, letters, and numbers are often used. These items are presented in rows on a card, and the student is asked to name each as quickly as possible. Naming speed, particularly letter naming, is one of the best early predictors of reading difficulties. Therefore, it is often used as part of screening measures for young children. Slow naming speed results in problems with developing reading fluency. It also makes it difficult for students to do well on timed tests. Students with both the naming speed deficit and the phonological processing deficit are considered to have a “double deficit.” Students with the double deficit have more severe difficulties than those with only one of the two.