This work’s purpose was to investigate relationships between language and musical aptitude, focusing on behaviour and the morphology of TTG in the auditory cortex. We used a longitudinal dataset of structural MRI data and behavioural scores from German-speaking children, measuring language and musical aptitude using the LLAMA and AMMA tests, as well as musical engagement. We predicted that there would be a positive correlation between behavioural measures of language and musical aptitude, and that we would find neuroanatomical differences in the TTGs in childhood that predict musical and linguistic skills in late adolescence. Neuroanatomical assessments were performed using automated tools, and statistical analyses included correlations and regression analyses. Our results did not support the initial prediction of a correlation between musical and language aptitude at the behavioural level. However, negative relationships were observed between the surface area of the right-hemispheric 2nd TTG and of the left-hemispheric 1st TTG with musical aptitude, indicating that a smaller surface area of these regions is associated with better melodic discrimination. The findings suggest that smaller and potentially more functionally efficient TTGs are associated with individual differences in aptitude for music, and that these anatomical features may be present earlier in childhood, possibly even before individual differences in musical aptitude manifest themselves.