Effects of adding interword spacing on Chinese reading: A comparison of Chinese native readers and English readers of Chinese as a second language

English is written with interword spacing, and eliminating it negatively affects English readers. Chinese is written without interword spacing, and adding it does not facilitate Chinese readers. Pinyin (romanized Chinese) is written with interword spacing. This study investigated whether adding interword spacing facilitates reading in Chinese native readers and English readers of Chinese as a second language. Participants performed two sentence-picture verification tasks with sentences written with pinyin or hanzi (characters). Interword spacing facilitated pinyin reading in English readers but not in Chinese readers; it did not affect hanzi reading in either group. The effects of interword spacing on second language reading appear to be determined by characteristics of both readers' first language writing system and the writing system being read.