What’s the purpose of the grave accent in French?
For those unfamiliar with it, it’s the one that slants down to the right, like so: à è. As far as I can tell, it doesn’t change the pronunciation of the letter, but I suppose it must have some use or meaning, even if only historical.
It can signal a difference in pronunciation. a in isolation in “standard” French can take on one of two sounds: compare chatte with pas. However, à is almost exclusively pronounced with the former (e.g., là), whereas â is almost exclusively pronounced with the latter (e.g., pâte). Note that French accents vary, especially among those for whom it is a second language, and that these sounds may be homophonous in your pronunciation.
Same goes for the e. The unaccented form can have at least three different pronunciations: compare the two es in fermer, and the one in double. When e receives a grave or circumflex accent, it’s always pronounced like the first e in fermer. When it receives an acute accent, it has a sound like the second. Again, accents vary; consult your local francophone for further study.
Oh, and in case context was not enough to disambiguate things, by
“accents vary”, I was referring to people’s pronunciation, not the
orthography. 
it’s mainly used to distinguish between homonyms like
ou and où (or and where)
accent aigu is to change the prononciation of a word like, Hélène and élève (would sound different without the accent aigu)
accent circonflex is usually an indication that a consonant (usually an “s” has disappeared from the word.
Like pâte was pasta, fenêtre comes from the latin fenestra, and so on…
Correct elfje.
dtilque, it does change the sound depending if it is accent aigue or accent grave.
ah, Zazie, t’es toujours dans le métro?
that was without a doubt the best French book I’ve ever read.
And Les Fleurs Blueues, ofcourse!
How about this “enhanced” version of the OP:
If I send some e-mail to a French-speaking person, and leave out ALL accent marks, is there any danger of confusion? I’m sure the recipient will chastise me for my laziness, but will my message ever be ambiguous? I know “elfje” cited the difference between ou and où (“or” and “where”), but I believe these two could be distinguished within the context.
most could, bradwalt, you’re right.
but the more you use the accents, the more used you’ll get to them.
BTW, a lo tof French people use the accents incorrectly…it’s such a damn complicated language, grammar wise, anyway.
I used to hate French (still have a mental block about speaking it…)
I email France every day and don’t have accents on my keyboard/computer, I type long texts with no accents whatsoever. It can be understood although some words would take an entire different meaning (a noun opposed to a verb if an accent is there), but people figure it out with the sentence it came in. (note that the emails are for friends and family, not business related, I would write correctly, accents and all, if it was.)
And, on another note, Zazie dans le metro is the book I had the most fun reading, even if a teacher made me. 
Thanks for all the replies. Apparently the distinction between the grave accent and the unaccented vowel is sufficiently subtle that they don’t teach it to high school French students. At least I don’t remember learning it, but that may be more a function of the too many years since high school…
OK, followup question. I knew that the circumflex was a residual of a lost S (didn’t know it could be other letters, too), but why do they keep that? Is there something significant about the S having been lost?
It doesn’t only indicate a lost “s”, it changes the pronounciation of the vowel. “ê” sounds like a longer version of “è”.
There is a clear difference between “è” and “é”. I’m going to attempt to illustrate this with English examples.
“è” sounds like the “ai” in “air”.
“é” sounds like the “e” in “ear”.
C’est clair maintenant?
Regarding accents in emails, I’ve found that in most accented languages I’ve seen or emailed in (Polish, Croatian and Hungarian), the accents are left out without really much confusion. Germans often use the “e” after an umlauted letter, but occassionally do skip it all together. If you just have a beginner’s grasp on the language, it can be a pain in the ass to decipher, but if you’re reasonably proficient, it’s not that much a problem.
Ah well, when it comes to German, the official spelling rules were reformed a couple of years ago. It is now correct to replace an umlauted vowel with the vowel followed by an “e”. They have also abolished the “ß” and replaced it with a double “s”. They can go to hell. I like umlauts, I particularly like the “ß”, and I will not follow these arbitrary rulings.
Die neue Rechtschreibung kann meinen Arsh küßen.
Lucky for you, then, the “rules” you mention are a complete lie. The spelling reform does not replace the umlaut, nor does it abolish the sharp s (though a double s is now mandated after short vowels). Please check your sources before posting.
Your advice on French pronunciation also highly dependent upon one’s native English pronunciation. For most speakers of American dialects and many speakers of British dialects, the French é and è sound nothing like the e in ear or the ai in air, respectively.
They are not a lie (http://www.neue-rechtschreibung.de/), but I’m guilty of jazzing a story up a bit for the sake of argument, sorry.
But for goodness’ sake, there’s no need to be quite that wound up about it. I mean, it was an incomplete and somewhat shoddy piece of information, but to call it a "complete lie is a little surplus to requirements.
And as for the British dialects and the pronounciation of “ear” and “air”, I was assuming a standard BBC Radio 4 kind of accent. And if you’ve never heard BBC Radio 4, then think of how any of the British bad guys in Hollywood movies would pronounce these words. Or any one of the Lord of the Rings cast members.
I stand by how é and è are pronounced though. I should know.
I
I still don’t see anything on that site about replacing umlauts.
I never meant to impugn your understanding of French pronunciation; I was simply drawing attention to the rather limited usefulness of your means of demonstrating this ability.
OK, OK, leaaaave it!
Calm down, we’ve all had a drink!
Uh, actually “é” is not so much like “ear” as an “eh” sound like "say, “may” or “pray.” Remember, there are a lot of English countries in which “ear” is pronounced like “eer” so your original comparisson may confuse a bit, though you were clear as you referred to BBC 4 English.
E.g. “pâté” sounds like “pah-tay” rather than “patty”.
The accent grave was correctly compred to “air” or “get,” “bet” or “Fred”!
And actually it’s only in the last couple of weeks, now that I’m teaching French to an entrenched anglophone, that I fully realized the nuances of “ô”, “â” and “ê”. It’s weird when you have to explain your mother tongue to someone else – makes you realize the little subtleties you take for granted growing up with it.
Just to clear this up – it’s pronounced “eer” in the UK too. As far as I know nobody pronounces “ear” to rhyme with “betrayer”.
See here for pronunciation of French ‘e’,‘è’, ‘é’, ‘ê’. There will be some variation among Francophone communities worldwide, but these rules will suffice in many areas.
American English equivalents:
é - like ai in hair, sans the r glide at the end. If you pronounce the vowels in hair and hate exactly the same (most don’t), this rule will only give you an approximation of the French sound.
’è’, ‘ê’ - like e in bet. This is a straightforward “short e” than most Americans were taught in elementary school.
e - can be pronounced as either of the above, depending on the phonetic environment. Also is pronounced as “schwa” in words like je, me, que (cf. a in English sofa). Plain e can undergo nasalization in French (e.g. genre, vendredi) when followed by n, but AFAIK, ‘è’, ‘ê’, and é do not occur nasalized before n (e.g. mène).
Other notes:
It seems that when the initial vowel in a French word is é, that accent aigu often indicates a lost s as well (été from Latin aestus, école from Latin schola, épée analagous to Spanish espada).
In French monosyllabic words that do not end in a silent consonant (excepting cases of liaison), e without an accent grave is usually pronounced as ‘è’, ‘ê’ when there are two consonants ending the word, as in belle, geste, telle. If the monosyllabic word closes with a single pronounced consonant, an accent over the e seems to be obligatory, as in mène, mère, bête.