Proto-Indo-European

A. English, like all languages, is the product of change from a former language: that is, English is one step along a path of continuous development. The furthest back we can trace English, then, is Proto-Indo-European.

B. At this stage, “English” is barely perceptible. Here is a piece of a folk tale constructed in the Proto-Indo-European of about 2500 B.C. (hypothetically, of course):

Tod kekluwōs, owis    agrom ebhuget.

that hearing    sheep  field      fled

“On hearing that, the sheep ran off into the plain.”

The word *tod eventually did become that, and believe it or not, *kekluwōs was a form of the verb that did eventually become hear. But field traces back to a Proto-Indo-European root meaning “to fill,” and flee to one meaning “flow”—these words are products of the semantic change.