This paper argues that Xianshui Song in the Guangdong–Hong Kong–Macao Greater Bay Area has migrated from boat-borne antiphonal practice to shore-based community settings and staged/touristic display, reshaping musical functions and formal features. Framing Xianshui Song as Lingnan intangible cultural heritage rooted in Danjia/Tanka communities and Cantonese varieties, the study examines how recontextualization alters melodic syntax, social roles, and identity marking. Research questions probe the effects of institutional safeguarding and venue change on tune-types and phrase structures (long/short), on social uses of antiphony, and on the phonetic–melodic alignment that indexes local language and belonging. The corpus integrates Macao and Hong Kong ICH entries, Zhongshan dossiers, and public recordings to build a cross-regional annotated dataset of lyrics, filler syllables, cadential formulas, and turn-taking patterns. Methods combine comparative corpus analysis with interactive sound-field experiments implementing four situational scenes—Qihang [Setting Sail], Zhengliu [Riding the Competing Currents], Guishi [Homeward to Market], Mianlang [Lulled by the Waves]—to model lived contexts. Implemented via Ableton Live, Max/MSP, and Arduino, three performance conditions—unaccompanied, template-constrained harmony, and free electroacoustics—are evaluated on recognition, intelligibility, and participation to test preservation versus transformation. Analytical outcomes formalize a computational “tune-grammar” that links melodic contour, phrase length, tune-type, and filler placement, while quantifying staging/education effects on stylistic simplification. Contributions include an open annotated corpus, an interoperable teaching/performing toolkit, and comparative policy recommendations for community-based safeguarding and intergenerational transmission. The project advances a model of technologically assisted revitalization that situates musical change within migration, language endangerment, and cultural governance in coastal South China, while addressing data governance and community consent within ICH frameworks.