The word "蝌蚪" is formed by combining two characters, each constructed as a phono-semantic compound. "蝌" incorporates the semantic radical "虫" (indicating a small creature) and the phonetic component "科" (suggesting the pronunciation "kē"). "蚪" similarly uses the semantic radical "虫" and the phonetic component "斗" (suggesting the pronunciation "dǒu"). Together, they create the disyllabic term for tadpole.