Another character for the word “rice plant” in Old Chinese

Two kinds of grain, “millet, 粟米 sùmǐ” and “husked rice, 稻 dào”, frequently appear in the Liye Qin Slips. Aside from these grains, another character seen in the Liye Qin Slips, nǎo, is thought to represent grain. It also represents the words for “brain, 腦 nǎo” in other excavated documents. Since the archaeological data show that rice cultivation was practised around the middle and lower Yangtze Valley, the homeland of Proto-Hmong Mien (formerly the state of Chu 楚地), the word for “rice plant, 稻 dào” seems to be a loanword from Proto-Hmong Mien *mbləu. The character nǎo is reconstructed as *nˤuʔ, which bears the same onset as the sound for “rice plant (or husked rice)” in North and East Hmongic languages nɯ (< *mbləu). Hence, we propose that the assimilation (*mbl- > *n-) in these languages could have occurred at the latest just before or after the Qin dynasty.