This study discusses the manner in which Atayal (Atayalic subgroup, Austronesian language family) underwent a semantic shift in time expressions such as “a little while ago,” “now, today,” and “morning, tomorrow.” In relation to this, the forms for “yesterday,” “a little while ago,” and “later” are also discussed. In Proto-Austronesian, the meanings of “morning” and “tomorrow” are inseparable, and this form is reconstructed as *dama. In earlier Atayal, sasan meant both “morning” and “tomorrow.” The Atayal form, sasan, “morning, tomorrow,” does not reflect *dama. This study examines the origin of sasan in Seediq (Atayalic subgroup), a language closely related to Atayal. In Seediq, the form for “now, today” is saða, and it later became saya. The ð dates back to the Proto-Atayalic *j; thus, a tentative form in Proto-Atayalic can be reconstructed as *saja, meaning “now, today.” The Proto-Atayalic *j is reflected as g, r, or s in Atayal, so *saja can be reflected as saga, sara, or sasa. The last form, sasa, may be related to sasan “morning, tomorrow.” It is likely that -an was attached, a suffix indicating time or space, resulting in sasa-an. Then, one of the a’s was deleted from the consecutive vowels, becoming sasan. Somehow, its meaning shifted from “now, today” to “morning, tomorrow.” This study proposes that this semantic shift was driven by another semantic shift relating to a Proto-Atayalic form, *sawni, which means “a little while ago.” This word extended its meaning to include “today in the morning” and then further extended to refer to “today”; it probably also referred to “now.” As sawni became “now, today,” sasan, the original word for “now, today,” shifted its meaning to “morning, tomorrow.”
