Feasibility of an “Alien Language” Task for Prosody Assessment in Children With Down Syndrome

Abstract

Background: Prosodic impairments are reported in children with Down syndrome (DS), yet current assessment tools often impose cognitive and linguistic demands that potentially obscure true prosodic ability. There is a need for accessible, low–verbal-load tasks to evaluate prosody in this population and other populations with limited verbal abilities. Objective: This proof-of-concept pilot study examines the feasibility and construct validity of an “Alien Language” task designed to elicit prosodic variation through imitation of nonlexical syllable strings under different pragmatic conditions. Method: Five children with DS completed a novel prosody task named “Alien Language” task involving repetition of consonant–vowel syllables produced as statements or questions or with emphatic stress. Acoustic measures of fundamental frequency ( F 0) and mean duration were extracted. Generalized additive mixed models (GAMMs) were applied to F 0 contours to assess condition-dependent prosodic variation and individual differences in intonation. Results: The task elicited systematic acoustic variation across conditions. Descriptive analyses showed higher F 0 and longer durations in emphatic and sequential conditions. GAMM results revealed significant time-varying effects for specific conditions and robust participant-level variation in F 0 trajectories. While most pairwise contrasts were not statistically significant in this feasibility study, patterns suggested sensitivity to subtle prosodic modulation. Conclusions: The “Alien Language” task appears to be a feasible approach for eliciting analyzable prosodic variation in children with DS. It enables evaluation of F 0 variation without lexical confounds and may serve as a foundation for future clinical and developmental prosody research. Further validation in larger samples is warranted.