Reconstruction:Proto-Tai/ŋɯəkᴰ

• *ŋɨɨk (per Vovin 2021:114)
• *ŋɨǝk (“saltwater crocodile → mythical sea monster”) (per Li, 1977)
• *ŋwak (“mythical water creature”) (per Chamberlain, 1977)

Unclear. Either:

• from Middle Chinese 鱷 (MC ngak) (Pittayaporn, 2009-2010:16); or
• of native origin (Vovin 2021:112-114), as:
  • 鱷 is attested late - for the first time in Shuowen Jiezi [c. 100 CE] as 𧊜 (EHC ŋɑk) and
  • Tai peoples in southern China, to denote the tropical saltwater crocodiles, would "weird[ly]" borrow a word from Chinese people in the distant and inland Yellow River's basin,
• both making 鱷 more likely a loanword from Tai into Eastern Han Chinese instead (ibid.).

Furthermore, Vovin considers Old Japanese [script needed] (-ni) in [script needed] (wani) another loanword from Tai (ibid.).

*ŋɯəkᴰ

1. crocodile

• Northern Tai
  • Zhuang:
    • Nong Zhuang: ngowg
    • Zuojiang Zhuang: ngweg
    • Yei Zhuang:
      • Po-ai: ŋɨɨk⁶
  • Saek: [script needed] (ŋuǝk)
  • Yoy: [script needed] (ŋɨǝk⁵)
• Central Tai
  • Nong Zhuang: [Term?] (ŋɨk⁵)
• Southwestern Tai
  • Thai: เงือก (ngʉ̂ʉak)
  • Lao: ເງືອກ (ngư̄ak)
  • Tai Dam: ꪹꪉꪀ
  • Tai Dón: [script needed] (ŋɨ⁴)
  • Lü: [script needed] (ŋɨɨk⁵)
  • Tai Nüa: ᥒᥫᥐ (ngoek)
  • Shan: ငိူၵ်ႈ (ngōek)
  • Ahom: 𑜂𑜢𑜤𑜀𑜫 (ṅük)
• →^? Eastern Han Chinese: 𧊜 (ŋɑk)
  • Middle Chinese: 鱷 (ngak)
• →? Old Japanese: [script needed] (wani, “crocodile, shark”) (Vovin, 2021:112-114)
  • Japanese: 鰐 (wani, “crocodile; shark (obsolete)”)

• Pittayaporn, Pittayawat (2009-2010) “Karsts, Rivers, and Crocodiles”, in South-East Asia Program Bulletin‎^[1], pages 13-17
• Vovin, Alexander (2021) “Names of Large Exotic Animals and the Urheimat of Japonic”, in International Journal of Eurasian Linguistics, number 3, pages 105-120
• Li, Fang-Kuei (1977) A Handbook of Comparative Tai, Honolulu: University of Hawai’i Press
• Chamberlain, James R. (1977) An Introduction To Proto-Tai Zoology (Ph.D.), University of Michigan