Reconstruction:Proto-Sino-Tibetan/nup ~ nip

• Proto-Sino-Tibetan: ?
  • Proto-Tibeto-Burman: *nup ~ *nip = *nuːp ~ *ni[ː]p (Matisoff, STEDT); *nuːp~ni[ː]p (Chou, 1972); *nup ⪤ nip (Benedict, 1972)

*nup ~ nip

1. to sink
2. (of sun, moon) to set
3. to enter

• Old Chinese:

  入 /*nəp/ (B-S), /*njub/ (ZS) ("to enter; to set (e.g. sun)")

  納 /*nˤəp/ (B-S), /*nuːb/ (ZS) ("to take in, to let in; to receive")

  內 /*nˤəp-s/ (B-S), /*nuːbs/ (ZS) ("inside, inner part")

  (入 in the oracle bone script)

  • Middle Chinese: 入 (ȵiɪp), 納 (nʌp), 內 (nuʌiH)

• • →   Japanese:  入 (にゅう, ​nyū)
          Korean:  입 (入, ip)
          Vietnamese:  nhập (入)

• • →   Japanese:  納 (のう, ​nō)
          Korean:  납 (納, nap)
          Vietnamese:  nạp (納)

• • →   Japanese:  内 (ない, ​nai)
          Korean:  내 (內, nae)
          Vietnamese:  nội (內)

• • →   Thai:  ใน (nai, “inside, internal, in ...”)
          Lao:  ໃນ (nai, “inside, internal, in ...”)

    • Modern Mandarin
      • Beijing: 入 (rù, /ʐu⁵¹/), 納 (nà, /na⁵¹/), 內 (nèi, /neɪ̯⁵¹/)

        (Note: 入 - irregular development from MC, perhaps due to taboo reasons, i.e. to disambiguate from the figurative sense "to fuck" of the same character, which is now represented by 日 rì.)

• Himalayish
  • Tibeto-Kanauri
    • Bodic
      • Tibetan
        • Written Tibetan: ནུབ་པ (nub pa, “to fall (gradually), sink, to set; to decay, to decline”), ནུབ (nub, “west”), སྣུབ་པ (snub pa, “to cause to perish, to suppress”)
• Lolo-Burmese-Naxi
  • Lolo-Burmese
    • Burmish
      • Written Burmese: နိပ် (nip, “to decline (e.g. price); to be suppressed, to settle, to be quelled”), နှိပ် (hnip, “to press; to massage; to stamp, to seal”)

• *lip ~ lup (“to sink into, to dive”)
• *s-ni(ː)p ~ r/s-njap ~ s-nu(ː)p (“to squeeze, to pinch, to press”)