BackgroundIt is well-documented that children with Developmental Language Disorder (DLD) have a higher likelihood of experiencing anxiety, as well as other socio-emotional and behavioural (SEB) difficulties. Despite this, there is little consensus as to how these difficulties manifest. This study aims to understand the prevalence of broader SEB difficulties and anxiety, informing intervention development by understanding the relationships between them.MethodsA mixed-methods, case–control study was conducted. First, an online survey was completed by 107 parents of either children with DLD (“DLD sample”;n= 57) or typically developing children (“typical sample”;n= 50), aged 6–12 years old. Binary SEB statements informed by previous qualitative work (e.g. “my child requires routine/sameness”; “my child has frequent tantrums”) provided an insight into the prevalence of SEB difficulties in both DLD and typical samples. Validated measures of anxiety, emotion regulation, intolerance of uncertainty, insistence on sameness, family stress and coping mechanisms were also collected. Correlation and mediation analyses were run using these validated measures to understand the manifestation of anxiety in children with DLD in more detail. Qualitative interviews were then carried out with a select panel of survey respondents (n= 4).ResultsThe DLD sample scored significantly higher on all binary SEB statements than the typical sample: experiencing anxiety (80.7%,p< .05), requiring routine and sameness (75.4%,p< .001) and emotional dysregulation (75.4%;p< .001) were the most common difficulties reported for children with DLD. Using the validated scales, family stress and coping mechanisms were found to only correlate with the manifestation of anxiety in the typical group, not the DLD group. “Intolerance of uncertainty” and “insistence on sameness” were found to fully mediate the relationship between DLD diagnosis and symptoms of anxiety. Parent’s interviews provided contextual support for the analysis, as well as highlighting sensory sensitivities as a focus for future research.ConclusionsParents of children with DLD appear to cope well with their children’s complex SEB needs. Intervention focussing on intolerance of uncertainty may help the management of difficulties with anxiety. Behaviours such as insistence on sameness should be investigated further, as potential indicators for anxiety amongst children with DLD.