Introduction The present contribution discusses the interplay between bilingualism and Developmental Language Disorder (DLD), i.e., a neurodevelopmental disorder that negatively affects children’s language expressive and comprehension abilities. Given the close resemblance between the developmental language trajectories of typically developing L2 children and language-impaired children, the risk of confounding a delayed yet normal development with a language disorder in the L2 population is very high. The current study discusses assessment tools and good practices that (Italian) school educators and health practitioners could adopt to disentangle these two dimensions early and accurately. It also reviews studies showing the ‘protective’ effects of bilingualism on DLD and, in this light, emphasizes the relevance of home language maintenance for a harmonic and complete bilingual development of L2 children with and without language impairments.  1. Italian L2 development and language impairments Over the last years, the Italian school system has witnessed a constant increase in the number of pupils with non-Italian citizenship. Nowadays, they represent around 10% of the whole school population and form a heterogeneous group, including children born abroad to non-Italian parents, adopted with international procedures, and those of nomadic ethnic groups (MIUR 2020). However, more than 60% of these pupils are second-generation immigrants, who use a minority language at home, and are exposed to Italian at around three years of age, mainly through daycare, kindergarten, and community lives. Although they grow up as almost simultaneous bilinguals, their exposure to Italian is inferior to that of their monolingual peers in both quantitative and qualitative terms. On the other hand, most of these children do not receive any formal instruction in their home language, which tends to be deployed in an exclusively oral dimension (Arici et al., 2020; Chini & Andorno, 2018) and demoted to the status of heritage language (Kupisch & Rothman, 2018). Combined with fragile L1 competence, delayed and insufficient exposure to the community language deeply affects the developmental profile of L2 children, who lag behind their monolingual peers across various language dimensions. The gap is especially evident in early childhood (3–6-years of age) when they typically engage in the process of learning Italian. The limitations are particularly manifest in vocabulary, which is smaller in size and quality in the bilingual population (Bialystok, Craik & Luk, 2008). However, difficulties also emerge in the oral expression of sophisticated morphosyntactic structures, such as Italian clitic pronouns (Vender et al., 2016). Phonological awareness, in comparison, appears as a spared domain in L2 acquisition, especially when the target language has a relatively simple phonotactic system. This is the case of Italian, where L2 children performed at the level of their monolingual peers across tasks of nonword repetition, rhyme detection, and <a name="__DdeLink__293_606444101">spoonerisms</a> (Vender and Melloni, 2021). Importantly, there are striking similarities between the developmental language trajectories of L2 and language-impaired children, who both struggle with vocabulary and morphosyntactic abilities across different languages (Håkansson & Nettelbladt, 1993; Paradis & Crago, 2000, 2004; Paradis, 2005). Preschool years are an especially critical age since, usually, it is in kindergarten that language impairments such as Developmental Language Disorder are first identified. Moreover, at this age predictors of future learning disabilities such as Developmental Dyslexia also tend to emerge. However, with L2 children, the risk of confounding some typical limitations of a developmental bilingual profile with actual language impairments is high. On the one hand, an excessive concern on the part of educators and parents could prompt a premature diagnostic process, which might result in the erroneous identification of a language disorder in these children – what is also called a mistaken identity (Paradis 2005). This is a feasible outcome due to the lack of norms for the bilinguals, who are assessed with tools designed for and tested on the monolingual population (Bedore & Peña, 2008). On the other hand, a real impairment could be misinterpreted as a delayed L2 acquisition, resulting in a wait-and-see behavior on the part of educators and families, which could cause, in turn, a missed identity (Paradis, 2005). 2. Clinical markers of DLD Since assessment tools and protocols for the diagnosis of language impairments are designed for monolingual populations, psychologists and speech therapists are often left with few resources for understanding whether a bilingual child is in need of special service, or whether instead her or his language development is following a normal path. Therefore, in an increasingly multilingual society, it is of utmost importance to identify specific tasks across language domains that may help the identification of language (or learning) disorders in bilingual children. This goal has especially been pursued by studies assessing L2 children’s performance in clinical markers of DLD (previously called SLI, Specific Language Impairment), which are highly specific and sensitive diagnostic tools that assist in the accurate identification of this disorder. As for Italian, a recent study by Vender et al. (2016) has investigated the performance of 120 early L2 Italian children with different L1s (40 L1 speakers of Albanian, 40 L1 speakers of Arabic, 40 L1 speakers of Romanian) and 40 age-matched monolingual children in two tasks recognized as sensitive clinical markers of DLD/SLI in Italian: object clitic production and nonword repetition, which measure morphosyntactic and phonological processing skills, respectively. The authors found significant qualitative and quantitative differences between the profiles of typically developing L2 children and DLD children in these two tasks. First, like children with DLD, L2 children underperformed their monolingual peers in the clitic production task. However, their typical error was the production of a non-target clitic (i.e., a clitic with wrong gender or number features), whilst DLD children typically omit the clitic altogether (Bortolini et al., 2006). Even more importantly, while children with DLD are significantly impaired in nonword repetition (a marker that applies across several languages and is typically regarded as a purely verbal test), no differences were found between L2 and monolingual children on this task.<a href="#_ftn1" name="_ftnref1" title="">[1]</a> These results suggest that, at least in Italian, it is possible to differentiate between L2 children and children with DLD. Specifically, a close inspection of their language profiles shows indeed that their resemblance is only superficial, and both clinical and educational practice should take advantage of these specificities of the two populations for ensuring more accurate diagnosis and targeted educational strategies. 3. Preschool L2 children and language development: the educators’ role Research on clinical markers has had a great impact on the development of tools for the diagnosis of language impairments but it has also led to the design of pre-diagnostic or screening tools that can be used by educators with preschool children. Educators, indeed, play a critical role in the early identification of potential deficits, as they inform the families about the presence of potential impairments in their children. Indeed, it is often in kindergarten, for DLD, and in primary school for learning disabilities, that educators identify children in need of special services and advise their parents about the opportunity of a clinical investigation of the children’s language or learning profile. However, in increasingly multilingual classes where pupils have different language backgrounds and learning profiles, the task may be extremely challenging, and teachers might inadvertently contribute to the late identification of language impairments in bilingual children. A screening tool for language impairments in Italian is CLAD-ITA GAPS (Vernice et al., 2013), a standardized test that can be administered by educators and parents to kindergarten children (4-5 years of age) when language impairments are suspected. The test is inspired by the English version of van der Lely et al. (2011), the GASP test, and adapted to the specificities of the Italian language and clinical markers. The CLAD-ITA GAPS test examines children’s phonological and morphosyntactic/syntactic skills through two psycholinguistic tasks, i.e., nonword repetition and sentence repetition. As explained by the authors of the test, the choice of these two areas is motivated by the fact that they are especially compromised in children with DLD, as evidenced by research on clinical markers.<a href="#_ftn2" name="_ftnref2" title="">[2]</a> Despite lacking a diagnostic value, the CLAD-ITA GAPS test allows non-professionals to highlight some difficulties in critical areas such as phonology and morphosyntax in very young children. Moreover, the administration of this screening tool to preschool and school children confirms that repetition tasks are a promising area for the identification of DLD at different stages of development. On the other hand, research has shown that typically developing L2 children are not impaired in nonword repetition. Therefore, the administration of such a test, in particular, may prove useful for differentiating between typical and atypical language profiles among L2 children. Another valid method for recognizing atypical language development in bilingual children consists in collecting precise data on their home language skills, as a low competence in the L1 might be a signal of language impairment (Erdos et al., 2014). This goal can be pursued through the administration of questionnaires to the parents, like The Alberta Language and Development Questionnaire (ALDeQ), developed by Paradis et al. (2010) and specifically aimed at evaluating clinical markers of DLD/SLI in sequential bilingual children. The Italian version of the ALDeQ parental questionnaire has been adapted to Italian and tested by Bonifacci et al. (2016). As in the original version, most questions aim at collecting information on children’s development in the L1 and in the L2. In particular, questions are organized in four sections collecting information on: A. the children’s early development in the L1; B. their current L1 and L2 skills; C. behavioral patterns and activity preferences (aimed at investigating markers of other developmental disorders, often in comorbidity with DLD); D. family history information. The administration of this questionnaire to the parents of 18 sequential bilingual children with DLD/SLI and 105 typically developing children revealed that this tool has considerably high sensitivity and specificity indexes. As stated by Bonifacci et al. (2016: 50), the ALDeQ parental questionnaire is “a reliable instrument to be used for assessing sequential bilingual children for whom clinicians and educators are in doubt of possible language impairments”. Therefore, educators too are now endowed with resources and tools that, especially if used in combination, may help them in the challenging task of identifying potential language impairments in L2 children and promptly advising parents about the need for further in-depth diagnostic evaluation. 4. Bilingual Children with DLD When a bilingual child is diagnosed as suffering from DLD, one of the major concerns expressed by families is that exposure to two languages might worsen their linguistic development, aggravating their difficulties. Unfortunately, the prejudice that bilingualism can negatively affect the child’s development is still quite widespread, with the consequence that parents of bilingual children with DLD are often advised to simplify the linguistic environment and to adopt a monolingual approach in communicating with their children. In most cases, this leads families to sacrifice their minority language and give up bilingualism, in the hope of allowing for better development of the majority language, which they perceive as more valuable since it is used in the community and at school. Although their concerns are well-understandable, it is of the utmost importance to emphasize that this decision not only will not reduce the child’s language problems but, on the contrary, it might even be counterproductive, inducing negative emotional states that might hamper the whole family’s psychological wellbeing. The fear that bilingualism can worsen the clinical picture of children with DLD, or that bilingualism could even be the cause of their language difficulties, is indeed in sharp contrast with the results of scientific studies, which suggest that exposure to two languages does not negatively hamper the linguistic development. Contrariwise, it has been shown that the weaknesses exhibited by bilingual children with DLD are very similar to those of monolingual children. Paradis et al. (2003), for instance, analyzed the spontaneous speech of French-English bilingual children with DLD (aged between 6 and 7 years old) comparing it to that of two groups of age-matched monolingual children with DLD speaking either French or English and examining, in particular, the use of tense and non-tense morphemes. Importantly, results showed that the three groups of children displayed similar patterns of development and similar difficulties, thus excluding that bilingualism can exacerbate their problems. Likewise, Gutiérrez-Clellen et al. (2008) reported that Spanish-English bilinguals and English monolinguals with language impairment performed similarly in verb finiteness and nominative subject use in spontaneous speech production. This confirms then that the weaknesses observed in bilingual children are not caused by bilingualism, but rather they are simply a manifestation of the DLD. Besides excluding that bilingualism can determine more profound deficits in children with DLD, it has been found that it can even be beneficial. Tsimpli and colleagues (2017), for instance, reported that bilingual children with DLD tested in Greek L2 were even more accurate than Greek monolingual children with DLD in the production of clitic pronouns in both elicitation and narrative retelling tasks, as well as in a second-order Theory of Mind task. Boerma and Blom (2020) investigated the executive functions of monolingual and bilingual children with and without DLD, and they found similar deficits in selective attention and inhibition in the impaired children; however, when their (lower) competence in Dutch L2, the language used in the administration of the experimental protocol, was controlled for, bilinguals with DLD showed an advantage in both verbal and visuospatial working memory. All in all, these results thus indicate that bilingualism does not cause more profound deficits in children with DLD, but that it can rather act as a protective factor, ensuring compensation for their difficulties. It is then very important that families be aware of the fact that sacrificing bilingualism will not lessen their children’s difficulties but will deprive them of the many benefits of bilingualism. The role of teachers, educators, and health practitioners is therefore crucial in spreading correct information and reassuring families, emphasizing the importance of maintaining the family language in all of its components in order to guarantee a harmonic and complete bilingual development of their children. 5. Conclusive remarks In this contribution, we have dealt with the interaction between Developmental Language Disorder and L2 development, discussing the delicate issues concerning the identification of this disorder in bilingual children and the effects that exposure to two languages can have on children with DLD. We observed that due to the similarities in the language trajectories of children with DLD and L2 children which can render it difficult to distinguish between the two, it is highly recommended in the diagnostic procedure to take into account the children’s performance with the clinical markers of this disorder (as nonword repetition, which is rather reliable across different languages) as well as the child’s language history, considering, in particular, their age of onset and their quantity and length of exposure in both languages. We also observed that bilingual children with DLD should not renounce one of their languages, as bilingualism does not hinder their linguistic development or worsen their difficulties, but it can on the contrary provide important advantages. Besides guaranteeing higher mental openness and better professional and cultural opportunities, speaking two languages can indeed be beneficial at the linguistic and cognitive levels as well. Families should thus never be advised to sacrifice their minority language for supposedly better development of the majority language: this does not only lack scientific support, but it can determine situations of great discomfort, even causing the isolation of the child from the family environment and the social and cultural community life, while also preventing other siblings to grow bilingual as well. Not to mention the fact that in some cases the suggestion of replacing the family with the community language is not even an option, as in the case of parents who are not proficient in that language as they learned it in adulthood, and risk providing a poor-quality input. Families should instead be advised to continue to use the family language, offering their children a rich and diversified input, not only in the orality but also encouraging early home literacy environment practices. 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Psicologia clinica dello sviluppo, 17(2). 291-314. <div>  <hr align="left" size="1" width="33%" /> <div id="ftn1"> <a href="#_ftnref1" name="_ftn1" title="">[1]</a>  In the literature, it is commonly recognized that nonword repetition allows for the appropriate identification of children with DLD, especially at preschool age (Archibald & Joanisse, 2009; Conti-Ramsden, 2003; Conti-Ramsden & Hesketh, 2003; Deevy et al., 2010; Gray, 2004). Nonword repetition also allows differentiating the profile of children with DLD from that of children from minority or culturally deprived backgrounds (Oetting & Cleveland, 2006) and of children with ADHD, Attention Deficit/Hyperactivity Disorder (Redmond, Thompson & Goldstein, 2011). Interestingly similar results have been reported for developmental dyslexia, since nonword repetition is also a critical tool for the identification of this learning disability, and it may be effectively deployed to identify dyslexia in the bilingual population (Vender et al., 2020). </div> <div id="ftn2"> <a href="#_ftnref2" name="_ftn2" title="">[2]</a> Actually, research has shown that some DLD children may exhibit specific difficulties in language areas such as pragmatics and vocabulary, while maintaining syntactic skills (see among others, Friedmann & Novogrodsky, 2008). </div> </div>