Why do keyboards use the QWERTY layout?

The QWERTY layout dates back to 19th-century typewriters. Christopher Latham Sholes and his collaborators arranged the keys to slow down common letter pairings and reduce mechanical jams in the typebars. The layout was first widely marketed by Remington in the 1870s and became popular even after the original mechanical reason faded. Once millions of people learned it, QWERTY became hard to replace because of habit and compatibility. Today it remains common on English-language keyboards largely due to historical momentum rather than ergonomic perfection.