I found something that may be of interest. Researchers try to make a correlation between stuttering and learning multiple languages. Quoted by Yairi & Ambrose (PhD researchers) in the book Clinical applications (2023): >The ability to speak colloquially in two languages is another cultural aspect that has received some attention in relation to stuttering. Does the introduction of a second language pose a risk factor for stuttering? The available data are scant and suffer from weaknesses identified earlier. Still, some of the past findings suggested that stuttering is more prevalent among bilingual than among monolingual speakers. > >Travis et al. (1937) reported a prevalence of 2.8% and 1.8%, respectively, in 4,827 schoolchildren. In South Africa, stuttering prevalence among bilingual schoolchildren was 2.16% as compared to 1.66% among monolinguals (Stern, 1948). This issue was also investigated in England with children who stutter (CWS) ages 8 to 12 years, concluding that bilingual children had an increased risk of stuttering as well as a lower chance of recovery from stuttering than either monolingual or even bilingual children who used only one language (Howell et al., 2009). > >The study, however, suffers some weaknesses. Additionally, other investigators found that repetitions, the disfluency type closely associated with stuttering, are the most frequent form of disfluency in bilingual children (e.g., Byrd et al., 2015). Although there seems to be a vague general impression that bilingualism poses a causal factor in stuttering, we agree with Van Borsel (2011) that much remains unclear. An important factor contributing to the lack of clarity is the very different forms of bilingualism that were often ignored in research studies. A recent extensive review of 50 articles concerning bilingualism and stuttering also concluded that current understanding of bilingualism and stuttering is limited (Choo & Ashley, 2020). > >The issue continues to be of importance to parents who are often conflicted regarding whether or not to encourage bilingualism in their youngchildren for fear of causing stuttering or making existing stuttering worse. Some research has concluded that bilingual speakers possess superior brain executive functionscompared to monolingual speakers, suggesting that bilingualism provides a form of neural reserve (Perani et al., 2017). > >A recent extensive meta-analysis of the literature has supported this conclusion (Anderson et al., 2020). Overall, early surveys reported asomewhat elevated prevalence (e.g., Travis et al., 1937), but a more recent study did not find appreciative deviation from prevalence in the population at large (Au-Yeung et al., 2001). Byrd et al. (2015) argue that bilingual speakers are at a higher risk of a false positive identification of a stuttering disorder. In a recent comprehensive review of the literature, Choo and Smith (2020) also emphasized the wide diversity among studies concerning defining bilingualism and criteria for counting those who stutter. Significantly,they concluded that speaking more than one language does not put a person at extra risk for stuttering. > >Yairi concludes the chapter with: "It is still unclear if bilingualism influences the incidence of stuttering and whether characteristics of stuttering vary across languages spoken by the same individual"