In either child or adult with a normal intelligence, learning disability may be expressed as a problem with listening, thinking, speaking, reading, writing, and spelling.
According to research, about 50% of all students, who are not specifically diagnosed with any specific disabilities, are poor readers. They may have problems with vocabulary, morphology, syntax and text processing.
During my teaching experience for the last 25 years in Israel and in US, I noticed significant differences in Hebrew language acquisition among students from different linguistic backgrounds. Language decoding is the process of translating print into speech by rapidly matching a letter or combination of letters (graphemes) to their sounds (phonemes) and recognizing the patterns that make syllables and words. To summarize my observations, Hebrew decoding proves to be more difficult for students whose native language is not phonetic, such as English.
According to studies, the countries whose language is entirely phonetic, such as Finland or Russia, have very low number of reading disabilities. In countries, such as Japan or Taiwan, where language is logographic or syllabic and does not use alphabetical system, dyslexia does not exist.
In the US, on the contrary, one third of all elementary school students have difficulties learning to read, because English requires larger measure of linguistic awareness and the sound-symbol correspondence is very inconsistent.
So, what is the main reason of reading failure propensity in the US? Research has repeatedly demonstrated that the root cause of reading failure is lack of phonemic awareness, which is ability to understand that a spoken word consists of sequence of individual sounds. If a child lacks this skill, he or she will have difficulty learning the relationship between letters and the sounds they represent in words. In addition, such children will have problems applying the letter/sound correspondences to sounding out unknown words. Therefore, it is essential that phonemic awareness skills be directly and explicitly taught to children who suffer from such problems.
Phonemic awareness must exist before letters are introduced. Otherwise, the phonics instruction will not make sense to the student. The next important step is phoneme/grapheme correspondence that teaches which sounds are represented by which letter(s), and how to blend those letters into single-syllable words.