**3. Main predictive factors of reading and writing**

A large number of studies have been carried out over the years, with different individuals at different ages and in different languages, in order to explain reading and writing and the appearance of learning disabilities. These studies assign varying degrees of importance to the various factors [19–28]. We analyze below some of the main predictive factors that have been recognized as important in a majority of studies from recent decades.

#### **3.1. Phonological awareness**

Phonological awareness makes it possible for the individual to operate with segments of speech, and refers to the awareness that words are made up of linguistic units like the syllable and the phoneme [20]. Different levels of phonological awareness are identified: syllabic, intrasyllabic, and phonemic. The literature includes many research studies that demonstrate that syllabic knowledge and especially phonemic knowledge are strong predictors of reading and writing in students with and without dyslexia at early ages (4–7-year-olds), and in languages with differing orthographic consistency such as Spanish, Italian, Greek, English, Chinese, Arabic, and others [21–28].

Most of these studies emphasize that phonological awareness is responsible for grasping the grapheme-phoneme relationship needed for reading and writing words of different lengths, consistency, and frequency. They also note that the relationship between phonological awareness and written language is stronger in transparent languages, and at early ages. The relationship declines with age [23, 24, 26, 29], and phonological awareness relates differently to different ways of measuring reading: accuracy, speed, and efficiency/fluency [21, 23–26, 28–30]. There is current debate about what variables intervene in reading in languages with different linguistic consistencies, at what age they have the greatest influence, and how these variables relate to other cognitive variables such as phonological memory, letter knowledge, and rapid automatic naming [25].

#### **3.2. Speech perception**

cognitive components (e.g., phonological awareness, decodification, vocabulary and comprehension), psychological components (e.g., motivation, locus of control, teacher expectations, gender differences, and learned helplessness), and ecological components (e.g., behavior at home, culture and parental involvement, classroom environment, peer influences, and dialects) [16, 17]. This model assesses reading and writing performance from a multidimensional perspective, and facilitates more adequate, individualized instruction, with better chances for

Finally, based on these research studies, some authors have proposed a fusion of the diagnostic and RTI models. This solution serves to evaluate students' skills and determine their academic needs, so that they may receive special education that is adequate for their needs

A large number of studies have been carried out over the years, with different individuals at different ages and in different languages, in order to explain reading and writing and the appearance of learning disabilities. These studies assign varying degrees of importance to the various factors [19–28]. We analyze below some of the main predictive factors that have been

Phonological awareness makes it possible for the individual to operate with segments of speech, and refers to the awareness that words are made up of linguistic units like the syllable and the phoneme [20]. Different levels of phonological awareness are identified: syllabic, intrasyllabic, and phonemic. The literature includes many research studies that demonstrate that syllabic knowledge and especially phonemic knowledge are strong predictors of reading and writing in students with and without dyslexia at early ages (4–7-year-olds), and in languages with differing orthographic consistency such as Spanish, Italian, Greek, English,

Most of these studies emphasize that phonological awareness is responsible for grasping the grapheme-phoneme relationship needed for reading and writing words of different lengths, consistency, and frequency. They also note that the relationship between phonological awareness and written language is stronger in transparent languages, and at early ages. The relationship declines with age [23, 24, 26, 29], and phonological awareness relates differently to different ways of measuring reading: accuracy, speed, and efficiency/fluency [21, 23–26, 28–30]. There is current debate about what variables intervene in reading in languages with different linguistic consistencies, at what age they have the greatest influence, and how these variables relate to other cognitive variables such as phonological memory, letter knowledge,

[18]. There is a great need for further objective research.

**3. Main predictive factors of reading and writing**

recognized as important in a majority of studies from recent decades.

success [17].

66 Learning Disabilities - An International Perspective

**3.1. Phonological awareness**

Chinese, Arabic, and others [21–28].

and rapid automatic naming [25].

Processes of speech perception refer to the preliminary, auditory perceptual analysis of words, taking into account their phonetic and auditory characteristics, and how their phonological representation is formed [19]. Speech perception has been investigated in children of different ages with and without dyslexia [31–34]. Ref. [31] analyzes the relationship between speech perception and reading of words, presenting word segments of progressively greater length. Speech perception is found to predict reading in novice readers but not in expert readers. Other authors consider that speech perception loses importance in typical readers as they acquire experience [25].

Some studies have found that deficits in phonetic discrimination produce errors in phonological representations of the lexicon, and therefore in phonological decodification [32–34]. Thus, readers with dyslexia present deficits in phonological processes due to difficulty creating phonological representations based on acoustic signals of speech [32]. In other words, they present difficulties in identifying and discriminating speech segments, specifically, identifying and discriminating consonants that differ in the place and manner of articulation and sonority [33, 34].

On the other hand, the relationship between speech perception and phonological awareness is unclear. Some authors indicate that children with dyslexia have deficits in phonological awareness due to their deficits in speech perception [35], and that speech perception is not directly related to reading words [36]. Others consider that speech perception is unrelated to phonological awareness [37] and that it is independently related to reading in the case of readers with dyslexia, but not in typical readers [38].

In conclusion, there is controversy about whether speech perception is a predictor of written language or of learning disabilities, and whether speech perception is related to reading in a direct, independent relationship [33, 34, 36–38]. There seems to be more agreement, however, that this relationship varies with the student's age and experience.

### **3.3. Alphabetic principle**

The alphabetic principle, or letter knowledge, is based on the correspondence between speech sounds (phoneme) and a written graphic transcription (grapheme). The alphabetic principle is based on the grapheme-phoneme conversion and makes it possible to decode a word by applying systematic association rules and joining the sounds to form words [19]. Children use letter knowledge for spelling and internally store the pronunciation of the word in order to facilitate access to the lexicon.

The importance of the alphabetic principle in written language depends on age and reading experience. Namely, there is a critical relationship between the alphabetic principle and reading when one first begins to read and write. In Ref. [39], letter knowledge is found to be one of the best predictors of reading words in 4-year-olds. Similarly, the importance of letter knowledge has been demonstrated in children with and without dyslexia between the ages of 4 and 7 years [40, 41].

Elsewhere, there is some controversy about the influence of letter knowledge in languages with different orthographic consistency. Some studies indicate that letter knowledge is more strongly related to reading in transparent languages than in nontransparent languages [19, 23], and others indicate that it is not relevant in the latter, given that there is no direct correspondence between graphemes and phonemes [28].

Other studies have demonstrated that letter knowledge is also strongly related to PA at early ages in languages with different orthographic consistency [39, 42], but they do not establish the nature of these relationships. More research is needed to determine relations between PA, letter knowledge, and reading-writing of words, in order to establish what variable precedes the others in languages with different linguistic consistency.

#### **3.4. Rapid automatic naming**

Rapid automatic naming, or naming speed, consists of naming different high-frequency visual stimuli, such as colors, objects, letters, and numbers, that are presented on multiple occasions in controlled fashion [43]. Rapid automatic naming is considered to be a measurement or index of phonological and visual recovery, depending on whether the items are alphanumeric (letters and numbers) or nonalphanumeric (colors and objects) [44].

Studies have focused mainly on the relationship of rapid automatic naming to reading, in students with and without dyslexia, at different ages and in different languages. Children with dyslexia have been found to be slower in naming high-frequency visual stimuli than children without dyslexia [45–47]. In Ref. [45], rapid naming was found to have a strong relationship with word-reading speed in children with dyslexia, but not with word-reading accuracy.

Most studies consider alphanumeric rapid naming to be a predictor of several reading measures in typical learners [21, 25, 44, 47]. By contrast, there is no consensus on the influence of nonalphanumeric naming: some studies find no relationship to reading measures, while others do [21, 24, 25, 40, 41, 44, 48, 49]. Consensus is also lacking as to what measure of reading is influenced by rapid naming, at what age, and with what type of language. Some studies find that rapid naming influences only measures of speed, at early ages, and more strongly in nontransparent languages, while others also find a relationship with reading accuracy, at a later age and in transparent languages [23, 25, 26, 40, 46, 48–51].

Finally, there are studies that try to clarify how rapid automatic naming relates to phonological awareness and other cognitive variables, in order to explain reading and writing in languages of different linguistic complexity. Some find that rapid naming is independent of phonological awareness and contributes differently to the explanation of word and pseudoword recognition [21, 45, 52, 53]. For others, rapid naming is indirectly related to reading, through phonological processing [54].

#### **3.5. Vocabulary**

The meanings of words constitute a representational system that makes up the lexicon of a language. When we speak of vocabulary, we refer to words that we know, in order to communicate with each other, both orally and in writing.

Vocabulary is also considered an important factor in the acquisition of reading and writing; when children have difficulties in vocabulary, they have also been shown to present problems in reading and writing. Some studies find that vocabulary is a facilitator in word recognition, in fluency, and also in reading comprehension for children with and without dyslexia [40, 55, 56]. A vocabulary deficit is reflected in problems with fluency and reading comprehension [57].

Vocabulary is also related to phonological skills. Phonological representations start becoming more specific with the development of vocabulary [31]; word codification and recovery require analysis of the linguistic segments that words are made of. In this way, deficits in vocabulary are accompanied by poor phonological representations, and therefore by difficulty with decoding processes that are involved in reading and writing [19].

Other authors find that vocabulary differences between children with and without dyslexia generally appear at older ages, when children already have a scholastic history. These authors consider that difficulties with written language are themselves the cause of these differences [58]. Some research defends a combination of vocabulary and other phonological measures in order to better explain problems with written language [48].

In conclusion, there is much need for research that analyzes the combined contribution of the main predictive factors. More clarification is needed as to how these factors affect different measures of reading and writing, in languages with different orthographic consistency or transparency, and at different ages [22, 24, 29].
