Another part of the visual block involves automatic retrieval of letters and words. This ability is needed to recall basic sight vocabulary for both reading and spelling. A student with initial weaknesses in this block is likely to have a slow reading rate in later years. Major problems with spelling, for example, can be due to poor orthographic awareness. A major part of the auditory block is an ability identified as phonological awareness.
Phonological awareness is the oral language ability to understand the sound structure of speech.
This awareness allows one to manipulate language sounds. As students learn an alphabetic language such as English, a critical first step is becoming aware that speech can be divided or sequenced into a series of discrete sounds, words, syllables, and phonemes, the smallest units of sound. In most instances, this awareness develops gradually during the preschool and early elementary years. Difficulties with reading and spelling can be caused by poor phonological awareness. Some students have trouble discriminating similar speech sounds and often omit sounds when spelling a word or confuse certain sounds, such as writing ck for ch.