ภาษาญี่ปุ่น-เกาหลีดั้งเดิม

Proto-Japonic-Koreanic (PJK) is a hypothesized common ancestor of the Japonic and Koreanic language families. The hypothesis is contested: Whitman (2012), Robbeets (2015) — and Robbeets et al. (2021) Transeurasian — argue for a shared ancestor whose speakers brought wet-rice farming from the southern Korean peninsula (Mumun) to the Japanese archipelago (Yayoi). Vovin (2010) and others reject the connection, noting that proposed cognates concentrate in cultural/farming vocabulary (rice, paddy, millet, silkworm) rather than basic vocabulary like water/fire/sun — which is the major reason the hypothesis remains controversial. Nearly all 20-word Swadesh-style cells here are intentionally left as "—" to reflect this gap.