Originally the word meant to sift, for example to remove refuse from
spices. With time its meaning became distorted to what it is now. From
Old Italian garbellare (to sift), from Arabic gharbala (to select).
Earliest documented use: 1483.
http://wordsmith.org/words/garble.html
I found the two meanings are quite different: the old meaning is to remove usually visible impurities from something (clear) while the new meaning is to distort (not clarify). Why did the meaning change so much?
Some dictionaries have removed the old meaning 'sift'. Is the old meaning still used now?
e.g. Google translates the "garbled" in "Garbled spices are less likely to contaminate a recipe. " into "mixed" while I think it means "sifted" in this context. Does "garble" still have its old meaning?
Best Answer
The meaning of garble as to distort began as a usage of its meaning "to sift" as to pick out parts of a speech or writing, as we would now say to "quote out of context" or to "cherry-pick".
By 1930, the word had begun to be used generally as "to confuse", but the meaning of "to cherry-pick quotes" was still common.
Since about 1950, the meaning has rapidly changed, being used as a term for radio interference, and for general confusion of meaning.
So we see a progression from
In the 1930s, both meanings were in use. After 1970 at the latest the last meaning has become almost exclusive. It seems to me that the most likely reason is the adoption of "garble" as a jargon term to mean radio interference, combined with the exposure of large portions of the population to radio communication during the second world war.
Discussion
In the early 1800's the meaning of garble as "to take out of context", generally deliberately, is well supported:
Johnson's Dictionary (1805) has:
Mr Pole's Justification of the arrest of the Catholic Delegates (1811):
Cobbett's Political Register, Volume 19 (1811)
Remarks by E Burke on mr Stanser's Exammination (1805)...
An Essay on the Law of Patents for New Inventions (1810)
Around this time I don'[t find any examples of "garble" as to "accidentally misunderstand or misquote".
Between 1850 and 1859 we find the same:
Notes and Queries, volume 9(1854)
Webster's Dictionary (1854):
The Parliamentary debates (1854)
From 1900 to 1909:
The Fortnightly Review - Volume 80:
By 1950 the meaning had begun to change.
Still in the old sense:
Encyclopaedia Britannica (1952)
And in the new sense:
Stories for Tomorrow: An anthology of modern science fictio (1954)
By 1975 most examples seem to be to do with radio interference.