A bibliometric comparison of grammatical development in spoken and sign languages: Thematic evolution and persistent keywords

This study offers a bibliometric comparison of grammatical research in spoken and signlanguages, focusing on thematic evolution and key anchors. Drawing on 22,947 spokenand 712 sign language articles (1989-2024), we applied Biblioshiny to extract andvisualize bibliometric indicators. Research periods were segmented using threedata-driven metrics—Annual Scientific Production, Average Citations per Year, andTrend Topics—enabling modality-specific periodization. Thematic evolution analysesrevealed a parallel three-phase trajectory in both modalities: foundational, growth, andexpansion. Spoken language research showed greater diversification, especially inpsycholinguistic and syntactic domains, whereas sign language studies remained centeredon modality-specific areas such as visual processing and accessibility. Persistent keywordanalysis underscored shared anchors (e.g., acquisition, syntax, perception) alongsidemodality-specific emphases. Despite dataset limits, this study advances a multimodalframework for grammar research, highlights gaps in sign language syntax andpsycholinguistic modeling, and outlines directions for cross-modal integration.