Los factores que propician la migración tlaxcalteca

Adequate spoken language development and subsequent literacy skills are essential for offering educational attainments, accessing the educational curriculum, achieving positive social and emotional development and improved life opportunities (Broomfield and Dodd, 2004; Lee, 2008; Snow and Powell, 2004; Snowling et al., 2001). The relationship between speech-spoken language and literacy has been explored in depth and discussed widely in the international literature, highlighting a strong interconnection between the above areas of development (Dockrell and Arfé, 2014; Ehren and Ehren, 2001; Hodson, 1994; Stackhouse, 1989). Before examining these associations in more detail it is essential to clarify that the area of literacy that is analysed here concerns the aspects of reading, comprehension, writing and spelling, taking thereby a rather ‘technical’ dimension which is widely met in the related literature and research in the UK and internationally (Martin and Miller, 2003). When exploring the interrelation, the similarities and differences of speech and literacy, it is made clear that in addition to spoken language the aspects of reading and writing are associated with ‘a more conscious level of awareness’, requiring the function of orthographic representations in order to convey/transfer the information (Blood et al., 2010, p. 417), whereas the aspect of syntax is rather complex. However, due to the involvement of the same language components (i.e. pragmatic or semantic) and skills there appears to be a strong link between oral language and literacy development. The ‘Emergent Literacy’ perspective which argues that the development of literacy skills starts at preschool age highlights the intimate relation of oral language abilities, reading and writing. In particular, in an attempt to identify the emergent literacy skills in children, Whitehurst and Lonigan (1998) suggested the emergence of two

areas/domains, the ‘outside-in’ and the ‘inside-out skills’54

. These seem to be related to children’s later word decoding, as through the skills that are included in these domains children are able to not only ‘translate a written word into sounds and sounds into written words’ (Curran, 2004, p. 29), but also to accomplish reading comprehension.

In parallel with the literature concerning the link of speech and literacy skills, there is also considerable theoretical and empirical work which drew attention to the relationship between the difficulties that are related to spoken language and literacy deficits that may consequently arise. Studies in this field indicated that children who experience difficulties/disorders with their speech and language are at high risk for poor literacy outcomes, whereas gradually a growing body of researchers, educators, psychologists and SLTs raised points of a continuum among the above areas of development (Bird et al., 1995; Catts, 1993; Glogowska et al., 2006; Schuele, 2004; Scott and Windsor, 2000; Stackhouse and Wells, 1997; Vlassopoulou, 2007; Webster et al., 1997). In particular, studies that examined children experiencing difficulties in the areas of language and articulation/phonology, while their cognitive abilities and sensory skills followed the typical development, indicated that these children are at risk for delayed acquisition of reading skills (Nathan et al., 2004a; Scarborough and Dobrich, 1990) and respectively those with reading problems are more likely to have SLD (Larrivee and Catts, 1999; Nathan et al., 2004a; Scarborough, 1990). Characteristically, the Rose Report (Rose, 2006) in an attempt to provide ‘ways forward’ and recommendations in order to build ‘quality rather than capacity’ (Rose, 2006, p. 6) in the programmes and practices applied to literacy teaching of early years reading, emphasised the fundamental role of effective communication skills for children’s well being55

and the close relation between the spoken language and literacy skills. This is indicated not only through the development of phonic abilities but also for reading comprehension (Catts et al.,

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Outside-in abilities involve information that is outside the printed word and affects the understanding of print, and oral language skills (e.g. semantics or vocabulary), whereas Inside- out abilities concern printed information, including phonemic awareness skills and letter knowledge (Curran, 2004).

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Supporting, entirely, through this point the intentions of the Every Child Matters agenda (Department for Education and Skills, 2003b).

2002), where inadequacies in these crucial aspects lead to drawbacks in curriculum access.

Although, an attempt to indicate the aspects that may increase the possibilities of the co-occurrence of these disorders is not a straightforward process, as the field of SLD involves a heterogeneous population (with a range of sub groups) and literacy constitutes a wide and quite complex framework, however the interactions of certain risk or protective factors in individual children may affect directly or indirectly56 the connection of the above disorders. The literature and studies sought to explore and indicate the causal factors that may influence the relationship of the above disorders. Specifically, it is suggested that in many cases poor phonological awareness and other phonological skills seem to be quite strong and consistent predictors of a child’s associated literacy difficulties (Cain et al., 2000; Carroll and Snowling, 2004; McDowell et al., 2007; Stackhouse and Wells, 2001; Stackhouse, 2000), whereas inadequacies at the level of phonological representation57 appear to have more effect on poor literacy skills than the difficulties that are related to peripheral (or not central) or articulatory aspects (Snowling, 2000). Additional support to the important role of phonological awareness is offered by Liberman’s theory (1997), which argues that speech and language influence reading development through phonological awareness.

Non-phonological language aspects (e.g. inadequate vocabulary knowledge), seem also to be related with subsequent literacy weaknesses and particularly comprehension difficulties (Bishop and Snowling, 2004; Clarke-Klein, 1994; Francis et al., 2005; Nation, 2005; Snowling and Hayiou-Thomas, 2006), although this link is not as yet clear. Apart from the above linguistic aspects, a

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Speech and language development, which constitutes a protective factor, may influence directly and indirectly reading acquisition. In particular, direct influences may occur when speech and language skills are highly supportive towards the development of reading comprehension, specifically at supralexical (i.e. semantic) level/layer (Storch and Whitehurst, 2002), while indirect influences might arise when fast growth in the development of vocabulary promotes the systematic division of ‘underlying phonological representations for words’, encouraging the development of decoding abilities (Rvachew, 2007, p. 268).

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Difficulties in phonological processing and underlying phonological representations are highly related to weaknesses in the areas of reading accuracy, phonemic decoding and spelling (Leitão and Fletcher, 2004).

range of non-linguistic factors, such as non-verbal cognitive ability, have also an active role in the literacy development of children who have SLD (Catts et al., 2002). Factors that concern the child’s environment, such as school-educational support or family socioeconomic status appear to encourage or discourage the co-variation of SLD and literacy difficulties (Nathan et al., 2004a). Moreover, the nature (e.g. expressive and/or receptive), level of severity and persistence of speech and language errors, along with a child’s age, constitute factors that increase or decrease the above overlap (De Thorne et al., 2006; Larrivee and Catts, 1999; Leitão et al., 1998; Raitano et al., 2004) as is also indicated by the ‘critical age hypothesis’ (Bishop and Adams, 1990; Nathan et al., 2004a).

This particular hypothesis suggests that children who have speech problems to the level at which it is essential to apply phonological abilities in order to learn how to read, are highly likely to experience literacy problems, while children who manage to overcome their speech difficulties at an earlier age appears less likely to experience reading problems (Carroll and Snowling, 2004). This quite challenging relationship which appears to change over time indicates that phonological abilities may increase the risk of the above difficulties coexistence when children first learn to read and tend to rely heavily on ‘sounding out words’ (De Thorne et al., 2006, p. 1282), while later it appears to be the use of semantic and syntactic skills for reading comprehension which contributes to this overlap and vice versa.

Nevertheless, children who continue experiencing both expressive and receptive language difficulties in later childhood, tend to have more severe literacy problems than those children who have problems with either expressive or receptive language, while they seem to have difficulties specifically with word reading and reading comprehension skills (Simkin and Conti-Ramsden, 2006). The enquiries regarding the exact nature of the relationship between SLD and literacy deficits seem to be highly related to the ability to predict children’s later or long term literacy outcomes based on their early speech and language skills. Additionally, the evidence of the related studies have implications not only for the early identification of children who are at high risk of experiencing SLD and subsequent literacy difficulties, but also highlight the importance of intervention approaches which may improve children’s speech and language skills and

address the associated literacy difficulties. The majority of studies which seek to identify children’s later literacy outcomes are longitudinal, while they vary in the nature and level of SLD severity, as well as children’s age. Children (at pre- school years) who have difficulties with their articulation and phonological processing (Speech Sound Disorder / SSD) are at higher risk for literacy difficulties and particularly for Reading Difficulties (RD)58 or Developmental Dyslexia (Bird et al., 1995; Larrivee and Catts, 1999; Naucler and Magnusson, 1998; Vellutino et al., 2004).

Converging evidence from studies that examined children who have difficulties with phonological awareness at an early age (5-6 years old) indicated later poor reading and spelling skills (at the age of 7) (Leitão et al., 2000, 1998, 1997; Rescorla, 2002), while further findings suggested that environmental and genetic factors59 seem highly related to subsequent reading problems (Hayiou- Thomas et al., 2010; Plomin and Kovas, 2005). Despite the scepticism concerning the genetic influences on the relation of speech, language and reading skills (Olson, 2004), emerging findings from longitudinal studies of pre- school twin, sibling and unrelated children underlined the genetic and environmental effects on literacy and particularly on pre-reading and early reading skills (Hohnen and Stevenson, 1999; Olson et al., 1994). Specifically, they suggested that in a positive learning environment the role of genes is responsible for a substantial rate of children’s differentiation in the above skills, while genetic limitations on linguistic rates for phoneme awareness and other language abilities, restrain the development of reading (Olson and Byrne, 2005).

58 _{Children with Reading Difficulties (RD) experience problems with ‘accurate and/or fluent word} recognition and spelling’, while they also experience ‘secondary difficulties in reading comprehension’ (Peterson et al., 2009, p. 1176). The coexistence of SSD and RD has a rate of nearly 25% - 30% (Gallagher et al., 2000; Lewis, 1996).

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The role of genetics which implies a genetic continuity between speech and reading, as well as language and reading was expressed through the proposal of ‘generalist genes’ (Plomin and Kovas, 2005). According to this idea a substantial number of the genetic effects on challenging behaviours and frequently met disorders seem to be quite broad across the typical range of behaviour, and to the greatest degree across various aspects of a disorder and different disorders/difficulties.

Nevertheless, indicating the existence of a genetic or environmental link does not specify the underlying systems that are responsible for the relationship between speech and language skills and reading ability (Scarborough, 2005). Although genetic aspects may influence speech and language ability which lead consequently to the development of reading skills, it is also possible that genetic factors apply on a common shared resource which is used by speech, language and reading and in the absence of a clear causal or underlying relation of the above skills. Therefore, as highlighted by Hayiou-Thomas et al. (2010), a sufficient explanation of the above challenging relationships may be offered by collecting evidence from various methodologies.

Despite the intimate and quite complex or multifaceted relationship of speech, language and literacy skills, not all children or young people who have SLD have associated literacy weaknesses. This may be attributed to the causal factors that were examined previously, including the nature and level of SLD severity the individual might experience. However, when attempting to explore the long term literacy and academic outcomes for pupils with SLD and associated literacy difficulties, longitudinal studies indicate that speech and language skills are related to literacy outcomes throughout schooling, highlighting thereby the essential role of communication (Conti-Ramsden et al., 2001; Stothard et al., 1998). The Foundation Stage, the National Literacy strategy, the Speaking, Listening and Learning Guidance (Department for Education and Skills, 2003d) in the UK and the Analytical Programme of Studies (APS) for primary education (Greek Government Gazette, 2003) in Greece constitute a few examples which emphasise the above intimate relationship, indicating the applied practices and programmes within the existing educational teaching and learning frameworks.