Reconstruction:Proto-Sino-Tibetan/klaʔ

• Proto-Sino-Tibetan: *gla-k ⪤ *kla-k (Matisoff, 2003)
  • Proto-Tibeto-Burman: *kla (Benedict, 1972); *kra and *glak (Sagart, 2006)

Sagart (2006) tries to split this root into *kra "throw down" and *glak "fall", with the former root for reflexes with medial -r- or without final -k and the latter for reflexes with medial -l- or final -k. This split does not actually work due to forms like Karbi klo and Mizo tla with medial -l- but no coda.

The comparison between the Mizo, Karbi, Lepcha, Jingpho and Burmese forms appears in Benedict (1972). A comparison to Chinese 落 appears in Matisoff (2003:480), while Sagart (2006) expands this comparison to Chinese 下 (xià) and also notes a comparison to a Japhug form. This comparison of 下 (xià) to rGyalrongic forms is reinforced in Zhang, Jacques & Lai (2019).

Jacques has demonstrated that the voiceless/voiced transitivity alternation in this root is triggered by a nasal intransitivizing prefix, not an *s- causative prefix, comparing Tangut and Japhug reflexes to the Burmese reflexes.^[1]

*klaʔ

1. to fall

• Chinese (see there for further descendants)
  • 下 (OC *m-ɡˤraʔ-s (B-S))
  • 落 (OC *kə.rˤak (B-S))
  • 露 (OC *p.rˤak-s (B-S))
• rGyalrongic
  • West rGyalrongic
    • Horpa
      • Tangut: 𗒯 (*khji¹), 𘖢 (*gji¹)
  • East rGyalrongic
    • Japhug: kra (“to cause to fall”), ŋgra (“to fall”)
• Lolo-Burmese
  • Burmish
    • Burmese: ကျ (kya.), ချ (hkya.)
• Proto-Kuki-Chin: *klaa, *khlaa
  • Central
    • Mizo: tla, thla, thlâk
• Jingpho-Asakian
  • Jingpho: hkrat
• Central Naga
  • Ao: tsük
• Karbi: klo
• Lepcha: ᰁᰫ (klú)