Developmental language disorder (DLD)—also known as specific language impairment (SLI)—is a neurodevelopmental disorder affecting around 7.5% of the child population (Tomblin et al., 1997; Norbury et al., 2016) with no significant difference in sex distribution (Calder et al., 2022). DLD is defined as a severe and persistent disorder in oral language acquisition and development, unassociated with a medical condition, such as hearing loss, intellectual disability, autism, or any neurological disorder or genetic syndromes (Bishop et al., 2016). Moreover, DLD may co-exist with other neurodevelopmental disorders such as attention-deficit, hyperactivity, motor, speech and behavioral problems, or dyslexia (Bishop et al., 2016).

Studies of children with DLD have found that they exhibit an heterogeneous oral language profile (Conti-Ramsden, 2008) which may, to differing degrees, involve one or several expressive and receptive language components and which affects social and/or school development (e.g., Leonard, 1998; Bishop et al., 2017). Previous studies have documented significant difficulties across the different components of oral language including phonology, morphology, syntax, vocabulary, semantics, pragmatics, discourse, and verbal learning and memory (Bishop et al., 2017). Research have found some phonological issues in productive phonology such as omissions of unstressed syllables and final consonants and changing syllabic structures (e.g., omitting final consonants and reducing consonant and vowel clusters; Aguilar-Mediavilla et al., 2002, 2007; Bishop and Clarkson, 2003; Gallon et al., 2007; Broc et al., 2013; Larkin et al., 2013). Additionally, children with DLD struggle with other phonological abilities, such as in phonological awareness abilities including complex tasks like deleting phonemes, substituting phonemes, or producing rhyming words (Thatcher, 2010; Vukovic et al., 2022; Korlaet et al., 2023). A considerable body of research has focused on studying morphological problems in children with DLD. They have deficits in the use of inflectional morphology, such as verb tense and agreement. Specifically, they omit the ending-s in the third singular person (e.g., ‘She read a book’ instead of ‘She reads a book’) and the past tense marker-ed (e.g., ‘Yesterday, I play with Rachel’ instead of ‘Yesterday, I played with Rachel; Van der Lely and Ullman, 2001; Abel et al., 2015). Research has shown that these children struggle also with functional words since they omit articles, pronouns and prepositions (Bedore and Leonard, 2001; Restrepo and Gutierrez-Clellen, 2001; Sanz-Torrent et al., 2007; Coloma et al., 2016). Children with DLD produce syntactically simpler sentences (Marinellie, 2004) and find it difficult to understand both complex syntactic structures, such as dependent clauses and passive sentences (e.g., Bishop, 1997; Leonard and Deevy, 2006; Novogrodsky and Friedmann, 2006; Montgomery and Evans, 2009; Van der Lely et al., 2011; Leonard, 2014). Different studies have analyzed vocabulary and semantics in children with DLD and have observed that they typically present smaller and less rich lexicons than their typical peers (McGregor et al., 2023) and show slower latency times and more errors in picture naming (Lahey and Edwards, 1996; Lahey and Edwards, 1999; McGregor et al., 2002). Moreover, in receptive single-word vocabulary tests, they tend to score within the average range but statistically lower than their matched TD peers (Gray et al., 1999; McGregor et al., 2002, 2013; Sheng and McGregor, 2010; Haebig et al., 2015). Furthermore, they show semantic impairments encompass problems with expressing or understanding meaning from word combinations (Katsos et al., 2011). In pragmatics, children with DLD have difficulties understanding figurative language such as metaphors, double meanings or idiomatic expressions (Norbury, 2005) and understanding communicative intentions (Andrés-Roqueta and Katsos, 2020).

Having these problems in oral language, children with DLD are very likely to also experience difficulties in literacy. Different studies have reported that they are at greater risk for reading difficulties than children with typical language development (TD) (Sanz-Torrent et al., 2010; Bishop et al., 2017; Adolf and Hogan, 2018). It has been estimated that around 50% of children with DLD present also dyslexia (Bishop et al., 2009; Ramus et al., 2013) and they may exhibit reading comprehension difficulties (Ramus et al., 2013; Gough Kenyon et al., 2018).

Regarding writing, according to Hayes and Flower (1980) model, the writing process can be divided into three stages: planning, translating, and revising. The planning stage involves generating ideas, organizing thoughts and ideas, and setting writing goals. The translation stage is where these ideas are transformed from oral language into written form, and the revising stage involves reading and editing the written material. Additionally, the Not-So-Simple View of Writing (Berninger et al., 2002; Berninger and Amtmann, 2003) which is a modification of the Hayes and Flower model that incorporates various cognitive and executive function components, including working memory, into the writing process. Thus, children with DLD are expected to face difficulties in producing written content due to their challenges both in oral language and executive functioning, particularly in working memory (Im-Bolter et al., 2006; Archibald and Joanisse, 2009; Montgomery et al., 2010; Ebert and Kohnert, 2011). Accordingly, different studies have found problems in written production in children with DLD (i.e., Broc et al., 2021; Tucci and Choi, 2023). Written productions can be evaluated accordingly through analyses of microstructure and macrostructure (Liles et al., 1995). According to Hughes et al. (1997), microstructure refers to the syntactic and lexical levels of the production, that is, the language form and content. It has been characterized in terms of productivity as well as complexity. Conversely, macrostructure denotes the hierarchical structure and coherence of the text beyond the level of a single sentence. The way the story’s episodes are arranged, how events are sequenced, and how the protagonists’ internal states drive or respond to the story’s events are all examples of macrostructure (e.g., McCabe and Peterson, 1984; McCabe and Rollins, 1994; Liles et al., 1995).

As far as we know, previous studies about writing in children with DLD have focused on analyzing the microstructure. Tucci and Choi (2023) performed a scoping review of literature focused on the effects of DLD on writing skills across the lifespan. Results showed that spelling may be the most vulnerable area for individuals with DLD. In this sense, previously studies show that children with DLD make a significantly higher percentage of spelling errors when producing written texts compared to TD children of the same age (Mackie et al., 2013; Williams et al., 2013; Dockrell et al., 2014; Reilly et al., 2014; Joye et al., 2019). For the most part, these spelling errors are due to phonological and morphological errors, which involve substituting, inserting or eliminating letters within a word (Mackie and Dockrell, 2004). Broc et al. (2021) conducted a scoping review about the nature of spelling errors in children with DLD across different orthographies. They divided the 18 reviewed studies into those based on dictation tasks and those containing written narratives because these two types of tasks involve different writing processes. In addition, they separately analyzed those two types of studies regarding the typology of the orthography of language in which they were carried out (opaque or transparent orthographic system). On dictation tasks, children with DLD produced more phonologically unacceptable spelling errors. These errors varied by age and by the nature of the words dictated. Moreover, children with DLD produced less phonologically unacceptable spelling errors when the spelling could be derived by applying one-to-one sound-letter correspondences (transparent orthographic system) than when the phoneme-grapheme correspondences were irregular (opaque orthographic system). On written narratives, they found that most of the studies to assess the spelling skills of children with DLD had been conducted in opaque orthographies and only identified one study conducted in a transparent orthography language, Spanish (Soriano-Ferrer and Contreras-González, 2012). Overall, on written narrative tasks, results were contradictory about phonologically unacceptable spelling errors. Some studies found more difficulties than the control groups (Mackie and Dockrell, 2004) but others did not replicate those results (Broc et al., 2013; Dockrell and Connelly, 2015). In the only study conducted in a transparent orthography (Soriano-Ferrer and Contreras-González, 2012) children with DLD produced more spelling errors that were phonologically unacceptable compared to their peers of the same age. However, both groups made four times as many errors when the phoneme correspondence was irregular, as opposed to when it was regular, resulting in observable errors. Finally, on written narratives, only studies conducted in opaque orthographies were reported to examine errors in inflectional morphological spelling. Children with DLD overall showed problems in their ability to accurately use inflections in their spelling. Error patterns in children with DLD were similar to younger language matched peers but more frequent than their age-matched peers.

Moreover, children and adolescents with DLD also may have difficulties with grammar, organization, cohesion, and length of written output (Tucci and Choi, 2023). They make more errors and omissions when writing nominal inflectional morphemes and using derivational morphemes (prefixes and suffixes) than age-matched children (Connelly et al., 2011; Mackie et al., 2013). For example, they produce more errors in the use of plural forms and past simple verb tenses (Windsor et al., 2000; Mackie and Dockrell, 2004; Larkin et al., 2013). Additionally, they use fewer words that contain prefixes, such as im/patient or dis/agree and suffixes, such as teach/er or profession/al (Mackie et al., 2013). Interestingly, these differences are still significant when children with DLD are matched with children possessing the same language skills. The percentage of omitted auxiliary verb be and content words—such as nouns as subjects—is also significantly higher than in TD children of the same age with a similar receptive vocabulary (Windsor et al., 2000; Mackie and Dockrell, 2004). Moreover, they display poorer lexical diversity (Scott and Windsor, 2000; Mackie et al., 2013; Williams et al., 2013; Levlin and Waldmann, 2020; Stuart et al., 2020). The differences are once again significant when children with DLD are compared to a younger cohort with the same language skills. Research has also shown differences in writing abilities to be significant when children with DLD are compared to younger children of a similar reading age (Mackie et al., 2013). In addition, written texts produced by children with DLD are also shorter (i.e., contain fewer written words; Mackie et al., 2013; Dockrell et al., 2014; Stuart et al., 2020; Ralli et al., 2021) and contain a lower percentage of meaningful syntactic units (T-units) and coordinated sentences than texts produced by TD children of the same age. The sentences in their texts are also significantly shorter and contain fewer words per clause (Scott and Windsor, 2000; Mackie et al., 2013).

Most of these studies about the characteristics of the written language in DLD have been conducted with English speakers, a language with an opaque orthographic system. However, English has a number of characteristics that make it very different from transparent orthographic system languages such as Spanish. First, Spanish has a simple phonological structure. It has approximately 23 phonemes and the majority of syllables follow a simple consonant–vowel (CV) structure and have limited clusters and blends (Gorman and Gillam, 2003; Goikoetxea, 2005). Therefore, in Spanish, segmentation of syllables at the level of onset–rime is often equivalent to segmentation at the phonemic level. For example, a Spanish speaker who segments the syllables of the word “casa” [house] into onset and rime (onset:“c,” rime: “a”) will also identify the phonemes that make up the word (/c/ /a/ /s/ /a/; Goswami, 2008). This is not the case for the English, where many onsets and rimes contain clusters of phonemes, as in “sport” and “cost” which must be segmented further (De Cara and Goswami, 2002). Spanish has a transparent orthography both in terms of reading and writing since practically every phoneme is represented by a single, unique letter. Thus, children need to learn fewer phoneme-to-letter conversions in Spanish than in English, where one phoneme can be represented by multiple spellings (as the phoneme /f/ in words like frog, tough, and photo). Moreover, Spanish is a morphologically rich language: it uses inflections to indicate the relationship between the elements; that is, the composition of the words changes (e.g., “casa” [house], “casas” [houses], “casita” [little house]). This implies important morphological changes in words that include a lexeme or radical morpheme, to which one or more grammatical morphemes can be added (e.g., cas-a, cas-as, cas-ita). Another feature of Spanish, as in other Romance languages, is that the order of the words within the sentence is flexible (e.g., “Juan ama a Maria” [“John loves Mary”]; “A Maria ama Juan” [“To Mary loves John”]; “Juan a Maria ama” [“John to Mary loves”]), although there is a basic order of words in the sentence (canonical order: subject > verb > object). In addition, Spanish is a pro-drop language that allows personal pronouns to be dropped in the sentence (“Juega al fútbol” [Plays football]).

Previous cross-linguistic research suggests that both the simple phonological structure of Spanish and its highly regular phoneme-to-letter correspondence facilitate the process of learning to read and write in Spanish children with TD (Müller and Brady, 2001; Seymour et al., 2003; Ellis et al., 2004; Ziegler et al., 2010; Florit and Cain, 2011; Castejón et al., 2015). In theory, this should also help Spanish-speaking children with DLD as they learn to write. However, to our knowledge only two studies have been conducted concerning written language production among the DLD population in Spanish (Soriano-Ferrer and Contreras-González, 2012; Buil-Legaz et al., 2023). Buil-Legaz et al. (2023) analyzed the difficulties of children with DLD in spelling. Participants were 18 children with DLD (aged 7;0–11;5, M = 8;4, SD = 1.25) and 18 children with DLD with TD (aged 7;0–11;6, M = 8;2, SD = 1.29) that completed a spelling-to-dictation task of words and pseudowords, where length was manipulated. They used digital tablets to collect data and obtain measures of accuracy, latencies and total writing durations. Results showed that children with DLD produced more errors, longer latencies and longer writing durations than age-matched children. Regarding accuracy, analysis of the errors showed that children in the control group produce few errors, most being substitutions, while children with DLD made more errors and of more varied types (substitutions, omissions and additions). Moreover, they were more affected by length on writing accuracy than the control group. Soriano-Ferrer and Contreras-González (2012) examined the written narrations and the influence of linguistic measures on narrative competence of children with DLD. Children did a written narrative task, where they had to recall, in writing, a story given to them previously orally twice. The story was composed of 19 propositions, with a simple grammatical structure. The children with DLD created short narratives, poorly organized and less cohesive. Also, their writings contained more syntax errors and had a higher proportion of phonologically inaccurate spelling errors in natural spelling but not in arbitrary spelling errors.

However, in these two previous studies, written performance was measured by single-word dictation (Buil-Legaz et al., 2023) and by a narrative based on a story given orally (Soriano-Ferrer and Contreras-González, 2012). As stated Broc et al. (2021), in dictated tasks the words to be written are predetermined while on written narratives participants can choose words they know, which may result in fewer spelling errors as they may opt for words they feel to spell. However, in the study of Soriano-Ferrer and Contreras-González (2012) children had to retell in writing a story given orally. Therefore, as far as we know, there are not any studies that analyze the production of expository texts in Spanish-speaking children with DLD. An expository text or informational text is a non-fiction text that gives facts and information about a topic. It aims to inform, explain, describe, or define a particular topic or subject. Its primary purpose is to present factual information, clarify ideas, and provide insights in a clear, concise, and organized manner. This kind of text is very common in subjects such as science, history and social sciences. There are several different types of expository structures. Meyer and Ray (2011) proposed six structures: compare-and-contrast, problem-and- solution, cause-and- effect, sequence, enumeration, and description. Each text structure type represents a distinct text organization and purpose. For example, description focuses on describing a topic, person, place or thing by listing a collection of its features or examples while. Expository texts serve as valuable tools for assessing writing abilities in children due to their inherent structure, which demands clear, organized, and coherent expression of ideas. Evaluating a child’s ability to comprehend, synthesize, and communicate information effectively can be achieved through their creation of expository texts (Fisher and Frey, 2017). In this way, the aim of this study was to examine and compare text writing of children with DLD in the production of expository texts in Spanish. More specifically, by looking at how these children and their aged-matched TD counterparts plan and encode expository texts, we sought to find out what variables are most frequently impaired in children with DLD compared to the TD group. We hypothesize that, given the errors that children with DLD tend to make in oral language, we expect to find significantly more difficulties in this population compared to TD children in all areas of writing. Specifically, we expect to find more inflectional morpheme and verb conjugation errors, as well as a higher percentage of omitted functional words.

This study was approved by the Universitat Oberta de Catalunya’s (UOC) Ethics Committee. Furthermore, it was conducted in accordance with the ethical standards laid out in the 1964 Declaration of Helsinki and subsequent updates (WMA. World Medical Association, 2013).

In this study we explored the Spanish writing abilities of a group of children with DLD in comparison to a group of sex-and age-matched TD children using a written expository text. We were particularly interested in analyzing the writing abilities of this oral-language-impaired population in Spanish. This language is characterized by simple phonological structure, transparent orthography, rich morphology and flexible word order like Spanish.

Building on previous research on English-speaking children with DLD, in this study we analyzed word omissions, inflectional morpheme errors and verb conjugation errors. The analysis showed that the ratio of word omissions, errors in inflectional morphemes marking gender or number, and verb conjugation errors were significantly higher in the texts written by children with DLD compared to TD children of the same chronological age. These results are similar to other studies, such as Mackie et al. (2013), Connelly et al. (2011) and Mackie and Dockrell (2004), who also found that children with DLD had trouble using gender inflectional morphemes, as well as plural (−s), past (−ed) and gerund (−ing) markers, in their writing. Another morphological measurement not reported in previous writing research but key among Spanish-speaking children with DLD are errors using functional words such as articles, prepositions and pronouns that are very frequent in oral language (Bedore and Leonard, 2001; Restrepo and Gutierrez-Clellen, 2001; Sanz-Torrent et al., 2008; Morgan et al., 2013; Coloma et al., 2016). In our study, the children with DLD produced texts with significantly more functional words errors compared to the TD group. All these errors are similar to those made by children with DLD when they express themselves orally, for example difficulties with verb morphology (i.e., No me gusta [:gustan] las avejas [:abejas] / I do not like [number error in Spanish] sheep [: bees]) and in the use of functional words, such as articles (i.e., …la [:las] leonas… / …the [sing.]: the [pl.] lioness…), prepositions (i.e., …pueden oir [:oír] [:a] distansias [:distancias]…/..They can hear [:from] distance) and pronouns (i.e., Mi [:la] raza de mi perro…/ my [:the] breed of my dog.). This clearly shows that such difficulties in oral language production also affect children with DLD’s writing.

Spelling is one of the most impaired aspects of writing among English-speaking children with DLD when compared to TD children (Williams et al., 2013; Dockrell et al., 2014; Reilly et al., 2014). Our results showed that in Spanish, children with DLD also made significantly more spelling errors than their age-matched peers. A more specific analysis showed that they make significantly more articulatory and arbitrary spelling errors. These results are in line with previous research by Mackie and Dockrell (2004), who concluded that most spelling errors are due to letter substitution, insertion or elimination and letter combinations that do not comply with spelling rules. Although the research sample in Mackie and Dockrell (2004) were English-speaking children, their results are similar to ours. This means that children with DLD exhibit difficulties with phonological awareness whether they speak a language with shallow orthography or one with deep orthography.

Children with DLD performed worse in most of the other writing variables compared to their peers in the TD group. These results suggest that children with DLD had more difficulty writing longer texts, i.e., they wrote significantly fewer words and significantly fewer sentences than TD children. Texts by children with DLD were also structurally simpler, contained a significantly lower percentage of subordinate clauses and were not as lexically rich as those written by the TD group. These results track with previous studies done on English-speaking samples (Scott and Windsor, 2000; Puranik et al., 2006; Dockrell et al., 2014; Reilly et al., 2014), where children with DLD produced texts with significantly fewer words and a lower percentage of syntactic units. Our research found no significant differences between the two groups regarding mean sentence length. These results are consistent with Puranik et al. (2006), who found that, despite significant differences between children with DLD and children with TD in sentence production, mean sentence length does not vary significantly between the groups. However, these results contradict research by Mackie et al. (2013) and Scott and Windsor (2000), who found significant differences between the groups, with children with DLD producing fewer words per clause than their TD peers. Regarding clause types, no significant differences were found between the groups in terms of the percentage of simple and coordinate clauses used. There was, however, a difference when comparing the two groups for percentage of subordinate clauses. Proportionally, children with DLD used significantly fewer subordinate clauses than TD children, which indicates that their texts were simpler and less structurally complex. These results were also reported by Mackie and Dockrell (2004).

Along with structural characteristics, this study also evaluated the grammatical richness of the texts. The texts written by the children with DLD contained significantly fewer adjectives, adverbs and connectors (i.e., they were characterized by poor lexical density compared to the same-aged TD children). Another characteristic not analyzed in earlier research related to children with DLD’s writing abilities is the role of pragmatic errors and semantic errors in written texts. We explored these characteristics and did not find significant differences between the DLD and TD groups in these areas.

Finally, we looked for code-switching in the written texts. This measurement was included because the children in our sample were bilingual, speaking both Catalan and Spanish. The results show that the ratio of language switch per word is significantly higher in children with DLD than in TD children, indicating a lack of consistency in language used while writing and supporting the idea that bilingual children with DLD code-switch more than TD children (Pert et al., 2004). This could also be explained as a difficulty in thinking of a word and using the same word in another language as a compensation mechanism. However, as regards oral language, both Gutiérrez-Clellen et al. (2009) and Sanz-Torrent et al. (2007) found that Spanish-English and Spanish-Catalan bilingual children with DLD, respectively, did not differ from age-matched control children in terms of code-switching. Future research might look more closely at code-switching in written texts by bilingual children to analyze the differences between oral and written language.

In summary, writing abilities of children with DLD in Spanish showed more morphology-related, spelling and other writing errors compared to their age-matched TD peers. These results highlight the limitations that children with DLD may face in school when instruction is based on written language, and how these can affect their academic performance.

This is the first study to explore the characteristics of expository text production in Spanish by children with DLD. However, there are a few areas for future improvement. Although we aimed to recruit as many participants as possible, the final sample consisted of 52 children (26 with DLD and 26 TD children). This sample size aligns with prior studies on English (e.g., Mackie et al., 2013; Dockrell et al., 2014; Andreou and Aslanoglou, 2022; Brimo et al., 2023) and Spanish (Soriano-Ferrer and Contreras-González, 2012; Buil-Legaz et al., 2023) writing abilities in children with DLD. However, our study included participants ranging in age from 7;11 to 15;8 years, representing a diverse range of ages. In order to further enhance the generalizability and reliability of our findings, it is recommended for future studies to expand the sample size and include a more specific age range. By increasing the number of participants and narrowing down the age range, researchers can obtain a more comprehensive understanding of the topic at hand.

Our study centered on the production of expository texts, a common school activity that requires children to plan, translate, and revise. Although we primarily focused on microstructure, the task also allows for macrostructure analysis (global structure and coherence), a crucial factor in gaging the quality of children’s written texts. This aspect could be examined in future studies. The expository text task is less controlled than other tasks like dictation, where evaluators can choose words with different spelling characteristics. When writing expository texts, children can use words they are familiar with, potentially resulting in fewer spelling errors as they may prefer words they can spell correctly. Additionally, even though we allowed unlimited time for children to write a one-page text, the length of their texts significantly varied. Future research should examine the microstructure abilities in children with DLD, and attempt to control the text length to yield a similar amount of information.

In conclusion, the findings from our study should be considered when planning and conducting activities with these children. We emphasize the value of using expository text writing in assessing children with DLD. It is a simple, quick method that yields substantial information about their language and writing skills. Additionally, it would be insightful to examine the effectiveness of interventions targeting oral language issues on improving writing impairments, and vice versa.

The datasets presented in this study can be found in online repositories. The names of the repository/repositories and accession number(s) can be found at: https://n9.cl/0er91.

The studies involving humans were approved by the Universitat Oberta de Catalunya’s (UOC) Ethics Committee. Furthermore, it was conducted in accordance with the ethical standards laid out in the 1964 Declaration of Helsinki and subsequent updates (WMA. World Medical Association, 2013). The studies were conducted in accordance with the local legislation and institutional requirements. Written informed consent for participation in this study was provided by the participants’ legal guardians/next of kin.

RB-C: Data curation, Formal analysis, Investigation, Methodology, Validation, Writing – original draft, Writing – review & editing. NA: Data curation, Formal analysis, Investigation, Methodology, Validation, Writing – original draft, Writing – review & editing. MS-T: Formal analysis, Funding acquisition, Investigation, Methodology, Supervision, Writing – original draft, Writing – review & editing. LA: Conceptualization, Formal analysis, Funding acquisition, Investigation, Methodology, Project administration, Supervision, Writing – original draft, Writing – review & editing.