Still Tongue, Silent Cues: A Systematic Review of Lingual Resting Posture

This systematic review examines non-speaking tongue posture (NSTP) and its relationship to speech sound disorders (SSDs) and orofacial development, emphasizing assessment methods and reported associations. Following PRISMA (2020) guidelines, PubMed, Scopus, and Web of Science were searched during a defined window (October 2024–April 2025), yielding 265 records. Eligibility criteria permitted studies published from 2000 onward; the seven included studies were published between 2007 and 2022. After screening, seven studies involving pediatric and adult populations met inclusion criteria. Studies linking NSTP to SSDs or orofacial outcomes were included, whereas studies focused solely on dynamic tongue movement were excluded. Low or anterior NSTP was consistently associated with anterior open bite, crossbite, and articulation errors. Assessment methods varied, with clinical observation most common, while three-dimensional ultrasonography showed promise as a reliable, objective alternative. Overall, NSTP appears clinically relevant yet understudied, underscoring the need for standardized assessment tools and normative data.