How to pronounce the "œ"?
In the French language, there is a magnificent letter whose name I did not know for a long time. Here it is: it is an "o" mixed with an "e".
It is a subtle intertwining of vowels in words like "cœur/heart", "bœuf/ox" and "œil/eye". And what is its name? "O e-dans-l'o", the French said to me. At first I understood "in the water", yes, in the water! But no, the "e" did not fall into the water but into the "o", the letter "o"; The "œ" is what we call a ligature, in other words the fusion of two letters, in this case the "o" and the "e".
It is said as a single vowel that the French pronounce "é" or "e", depending on the word. And when it is written in capital letters, it gives this: Œ
But beware, not all "o" followed by an "e" are necessarily "œ". In "coexistence" or "mellow", for example, there is nothing fusional: the letters "o" and "e" are written and pronounced separately. This is not the case in "coeur/heart", "bœuf /ox" and "œil/eye".
Greek words or words ending in a consonant sound (r, l, f)
So where does the "œ" come from? Well, as you know, most words in the French language come from Latin or Greek. Greek has the diphthong "oi". In Latin, it becomes "oe" and then, when it arrives in France, it contracts into our ligature "œ", which is found in French words from Greek such as "œnologie", "œdipe", "œcuménique" and "œsophage".
And here, listen to me carefully because what you, the French, ignore most of the time is that, in these words coming from Greek like "oenology" you should pronounce this "œ" "é" thus saying é/nologie, é/cumenique, é/sophage. Well, that's the theory, because in practice, almost everyone says "oenology" like "vœu/vow" or "nœud/knot"!
But be careful, the "œ" is pronounced a little differently when it is followed by a voiced consonant : "cœur/heart" "bœuf /ox" or " œil/eye". As you can see, there are three ways of pronouncing œ: [e] [ø] [œ].
Is the "œ" on the way out?
Unfortunately, the œ is becoming increasingly rare nowadays because, from the Internet to SMS and newspapers, it is often written as a separate 'o' and 'e'. This is because, obviously, the vast majority of the population is unable to type the "œ" on a keyboard.
Well, it's true that most of the time, the automatic correction takes care of it, like here for the word "sœur / sister". Here, for those who don't have the automatic correction, is the magic formula to type the "œ" manually: if you have a Mac, press ALT + o, ALT + ö and if you have a PC, ALT + 0156.
Well, now you have no more excuses. Please write "œuvre / work", "cœur / heart" and even "vœu / wish" again! And even words as unappealing as "œstrogen" or "œsophagus" take on a whole new, almost poetic dimension thanks to the magic of the "œ", don't you think?
Oh, I almost forgot: there is also an e-in-l'a in the French language and it was Serge Gainsbourg who immortalised it in one of his songs: listen to "Sur ma Remington portative, j'ai écrit ton nom Laetitia, elle a ea t i t i a" ;"…On my portable Remington: I wrote your name Laetitia Elle a æ t i, t i a..."