Little is known of the language's prehistory, or when it first appeared
in Japan. Chinese documents from the 3rd century AD recorded a few
Japanese words, but substantial Old Japanese texts did not appear until
the 8th century. From the Heian period (794–1185), there was a massive
influx of Sino-Japanese vocabulary into the language, affecting the
phonology of Early Middle Japanese.
Changes in Late Middle Japanese (1185–1600) brought it closer to the
modern language, and the first appearance of European loanwords. The
standard dialect moved from the Kansai region in the south, up to the
Edo region (modern Tokyo) in the Early Modern Japanese period (early
17th century–mid 19th century). Following the end of Japan's
self-imposed isolation in 1853, the flow of loanwords from European
languages increased significantly, and words from English roots have
proliferated.