Proto-Chinese and Proto-Tibeto-Burman had many different prefixes and suffixes. Proto-Chinese changed to Old Chinese around the Shang Dynasty. This is shown in the Book of songs. Nouns, verbs, and modifiers were all dependent on affixes (beginning of words) such as *s-, *p-, *-k. After the Warring State Period in China, Old Chinese started using tones. The suffix (end of words) *-s was also used.