What you are hearing is most likely the correct Greek pronunciation of Elláda (Ελλάδα). This is the modern Greek word for the name of their country, ultimately derived from the Ancient Greek Hellás (Ἑλλάς).
The English name for the country, "Greece", derives from the Latin name "Graecia". Wiktionary gives a fairly full etymology:
From Latin Graecia < Ancient Greek Γραικός (Graikos), a character in Greek mythology, the son of Thessalos, the king of Fthia, from whom Ἑλλάς (Hellas, “Greece”) and Ἕλληνες (Hellenes, “the Greeks”) got their names.
Although this entry explains the etymology of the name "Greece", it is admittedly slightly confusing about the etymology of "Hellas". This page gives a hypothetical etymology:
Etymology: From Ancient Greek (Hellas
"Greece"), from prefix - (el-ελ "sun,
bright, shiny", (elios, "sun")) +
(las-λας "rock, stone"). : "The land of
the sun and the rock".
I would not however want to comment on the veracity of this source. All that is known for sure is that Hellas originally referred to a small area within Ancient Greece and only later came to refer to all Greece. This Yahoo answer gives some handy details.
Edit: found the citation from 1672, from Andrew Marvell’s The Rehearsal Transpros'd:
Two or three brawny Fellows in a
Corner, with meer Ink and
Elbow-grease, do more Harm than an
Hundred systematical Divines with
their sweaty Preaching.
It's also defined in B.E.'s A New Dictionary of the Terms Ancient and Modern of the Canting Crew, in its several tribes, of gypsies, beggers, thieves, cheats, &c. with an addition of some proverbs, phrases, figurative speeches, &c., c.1698:
Elbow-greaſe, a deriſory term for
Sweat. It will coſt nothing but a
little Elbow-grease ; in a jeer to one
that is lazy, and thinks much of his
Labour.
I found no earlier mentions than senderle, but here are some useful references. These are the earliest references I could find, and helpfully, they are also dictionary definitions.
The Online Etymology Dictionary says
Phrase elbow grease "hard rubbing" is
attested from 1670s, from jocular
sense of "the best substance for
polishing furniture."
There's a similarly colourful definition in Francis Grose's 1785 A Classical Dictionary of the Vulgar Tongue:
ELBOW GREASE, labour, elbow grease
will make an oak table shine.
(The rest of this dictionary is interesting too!)
Also, very pertinent to the question, here's The Royal Dictionary, French and English, and English and French by Abel Boyer in 1729:
Elbow-grease, (or Pains) Rude travail.
Rude travail is French for rough work. There's no entry for "l'huile de coude" in the French side.
And in John S. Farmer and W.E. Henley's 1905 A Dictionary of Slang and Colloquial English:
Elbow-grease. Energetic and continuous
manual labour : e.g. Elbow-grease is
the best furniture oil : Fr., huile de
bras or de poignet ; du foulage
(1779).
French huile de bras or de poignet is oil of the arm, wrist which is quite close. I think du foulage is fulling, the manual scouring and milling of cloth.
The earliest French reference I could "l'huile de coude" helpfully explains the term. In Jean Humbert's 1852 Nouveau Glossaire Genevois: Volume 1 (New Geneva Glossary):
Dans le langage badin des domestiques
et des maîtresses, l'huile de coude,
c'est le frottage, c'est-à-dire : Le
travail de la servante qui frotte.
Ces meubles, Madame, ne veulent pas
devenir brillants. — C'est que, ma
mie, tu y as sans doute économisé
l'huile de coude; c'est-à-dire : Tu as
trop ménagé ton bras et tes forces.
A rough translation:
In the playful language of servants
and masters, elbow grease is rubbing,
i.e. the work of the maid
who scrubs. This furniture, Madam,
does not want to shine. - My dear,
that is because you have undoubtedly
skimped on the elbow grease. In other
words, you have conserved both your arm and
your strength.
These references also suggest that "l'huile de coude" is an anglicisme.
Best Answer
It's just an incorrect tense construction of the verb that passed into common usage.
Verb tensing requiring a change in vowel is among the hardest area of grammar to create hard and fast rules for. The majority of past participles just add "ed" (or sometimes just "d"), such as walked, soaked, etc.
However, when that doesn't work there are really no good rules to say how the vowel should change. There are also some distinctions originally made between various past tenses that have been lost in colloquy; for instance, different conjugations ("it stank", but "I stunk") or between various past tense constructions resulting in passive/active voice differences ("I sang", but "the song was sung").
"Sneak" is a verb that is technically regular in past participle formation ( add -ed to form "sneaked"), but because it is phonetically similar to some exceptions that change the present tense vowel to "u" (stunk, sung, sunk), the vowel change is becoming acceptable for this word as well. Gotta love the organic nature of human language.
EDIT: Further exercise of my "Google-fu" has brought up this blog, which in turn references this BBC article. It appears that the word "sneak" is the latest of a series of verbs that have undergone "weak to strong drift".
To explain (hopefully consicely): early Anglo-Saxon language categorized verbs in several classes depending on how their various forms were constructed. This ancient system is where we get such peculiarities of tensing as bring/brought, think/thought, see/saw, fly/flew, and sing/sang/sung. Over time, the various verb classes coalesced into two: verbs that formed the past participle by simply adding "-d"/"-ed" were "weak", and verbs that formed the past participle any other way were "strong".
It is unusual but not unheard of for a verb's conjugation and tensing rules to change. However, when it does, it's usually "strong to weak"; conjugation and participle construction are simplified from the complex vowel-changing rules to easy suffixing. The word "glide" used to have the past participle "glad", which has been completely abolished in modern usage in favor of the "weak" construction "glided".
However, "sneak", and words that have gone before it like "dig", "string" and "dive", went the other way; they went from simply adding the suffix to changing the vowel. "Digged" became "dug", "stringed" became "strung", and "dived" became "dove". In this same way, "sneaked" is becoming "snuck"; the word "snuck" is already generally accepted as "sneak"'s past participle in most of the English-speaking world except for Britain. Eventually, it is thought, those tea-timers will give in to the pressures of the colonies.