Image source: 康殷《古篆文部首》
Is it true that the word relating the idea of a pig is and will always just be 猪(zhu1) in Chinese? Probably not. Besides 猪, 豬(zhu1), 豕(shi3), 彘(zhi4), 豚(tun2) etc. are also words for pig. A modern native might not write them daily, their influence stands. For instance, 彘, pronounced as “di1” in the Min language, is still said commonly to refer to a pig, and 豚 is broadly used in Japanese, such as in one of Studio Ghibli’s animes “紅の豚”, which illustrates the legend of a pilot, an anthropomorphic pig.
In Simplified Chinese, pig is written as 猪, where 豕 is replaced by 犭 (quan3), which means “dog,” whereas the 豬 in Traditional Chinese and the 豚 in Japanese still keep the 豕 component. On the other hand, Vietnamese, heavily influenced by Chinese culture, seems to follow the new trend of using 犭 as well.
Though 豕 might look remote to Simplified Chinese users, 家(jia1) is nevertheless a household word. How did 家 come to its meaning? In ancient times, having a pig under the roof meant good fortune for marriage. Isn’t Chinese fun?
One picture from Hayao Miyazaki’s 紅の豚:
(My Chinese zodiac animal is also pig.)