Zi Collection, Upper Volume Radical: Person (rén) Page 31, Entry 06 "The" (Tangyun) states it is pronounced tu (level tone) with the rhyme of he, and "Jiyun" states it is pronounced da (level tone) with the rhyme of he, with the same pronunciation as "ta". "Shuowen Jiezi" explains: To pound again after pounding is called "ta". "Zhengzitong" states: Nowadays, people set up stone mortars and use their feet to tread on pestles to pound rice, which is called "ta".