My approach to the analysis of idioms is based on determining the etymology
of the idiom. It is no better or more accurate than the determination of the
etymology of any other word or phrase. However, the phonetic aspect is often
easier because most idioms have more syllables than most single words.

To use an idiom properly does not require any knowledge of its etymology.
However, this knowledge may help an L2 student remember an idiom and
how/when to use it.

When I was a young kid, all of my friends and I knew the meaning of "escape
by the skin of my teeth" and not a single one of us knew it was the
translation of B'3or SHinai, a Hebrew pun on the word B'QoSHi (which means
barely, hardly, with difficulty) in the biblical book of Job 19:20.

The majority of idioms are transliterated (not translated) from a foreign
language directly into words that look/sound/feel like the target language.
For English idioms, there are not a lot of foreign languages involved:
Germanic languages, Latin, Aramaic (during the 600 years it was a lingua
franca), French (1066), Hebrew & Greek (biblical translation), Arabic (7
Crusades, Spanish Armada 1588 => Black Irish), Yiddish (in England prior to
the Expulsion in 1290; 1840s from Germany, early 1900s from Eastern Europe),
etc.

A minority of idioms are the translation of foreign idioms. These are more
difficult to analyze because one needs to know not only the language of the
source but also the foreign language into which the transliteration (sic)
was made, which may or may not be the same. Additional intermediate
translations should not affect the result if they were faithful.

For example, "(Does that) ring a bell?" means "cause you to remember something". The bell is proabbly a translation of French cloche or German Glocke used as a pun on the Latin verb recollect(are) = to remember.

A cute translation idiom is "count sheep !" to go to sleep. This is probably
the translation of a Hebrew pun S'PoR TSo@N on the Latin phrase sopor (as in
soporific) sond (as in soundly / deeply). This English idiom has been
retranslated back into Israeli Hebrew as LiSPoR KeVeS = to count sheep.

In a few cases, the "original" was a euphemism and not "plain text". I
suspect this is the case with "kick the bucket". It seems to be the direct
transliteration of a Semitic euphemism for dying: to make love in Paradise.
Using 3 for aiyin with its ancient G/K-sound: 3aGaV = make physical love +
B'3aiDeN = in Eden. 3G => Kick, vB3Dn => BucKeT.

In other words, this type of idiom formation represents the target
languag-ification of a foreign word or phrase. It can be most easily
illustrated with a foreign phrase that did *not* become an idiom: Latin e
pluribus unum = out of many, one. This is a motto of the USA. If it had
become an idiom, it might have become "a flower bush you name" but would
retain its original Latin meaning. It would probably acquire a folk
etymology, such as: we could give a flower bush many names, but we usually
give it only one.

Transliteration idioms are most easily formed at a time when most
target-language speakers do not read and write. They hear a foreign
word/phrase, understand its meaning in context, and convert its sounds into
target-language words they do know.

For a rare modern example, "face the music" is attested in the United States
from the 1840s. This "music" is probably from Yiddish MoSKoNeh = inference,
deduction, hence, consequences, from Hebrew MaSKaNah with the same meaning.

Etymology is not an exact science. The 3 etymologies that a non-linguist is
most likely to "know" are all false. Muscle is not from Latin musculus = a
small mouse. Sabotage is not from French sabot = an old shoe. And cabal is
from Hebrew het-bet-lamed = to plot, scheme, not from Hebrew Kabbalah =
esoteric knowledge, literally, received (tradition). Porcelain has nothing
to do with a porcine vulva, and gossamer is from Latin Gossypium = cotton,
not from goose + summer :-). But that is another story.

For more examples of idiom etymologies, do a Google search for < idioms
Hebrew "izzy cohen" >

Best regards,
Israel "izzy" Cohen
http://tech.groups.yahoo.com/group/BPMaps/