Orthography /Pronunciation consistency
To me, one of the biggest contrasts in pronunciation between English and French, is that English seems to have its orthography (spelling) much more disconnected from its pronunciation than French does. The contrast is even more pronounced between English and most other European languages such as Spanish, Italian, German etc...
What is the nature of this disconnect, and how can I best describe it? Let’s start with a simple, yet revealing example:
- I want to record this program
- I want a record of this program
These two sentences look very similar, and have a very similar meaning. The word «record» is used in both. However, the rules of English pronunciation dictate that these two words should be pronounced rather differently.
The first difference is in the emphasis: it is placed on the second syllable of the first «record», and on the 1st syllable of the second.
Using IPA phonetics, the first «record», which is a verb, should be pronounced [rikôrd’]; the second, which is a noun, should be pronounced [rek’ərd].
What about the two letters «ea»? Should they be pronounced like [i] as in «ear»? Or like [eə] as in «bear»? Or maybe like [ɜ] as in «heard»? You can see the difficulty associated with learning to speak English, even though you may have already learned how to read and write it fluently.
In French, this difficulty is greatly reduced. A letter or group of letters is always pronounced the same way, no matter the context. The main question is: should the letter be pronounced at all? Many consonants at the end of words are not pronounced (and no «E«s are ever pronounced at the end of words), unless the rule of liaisons applies.
By group of letters I mean that sometimes, two or three letters will combine to form a different sound than would be otherwise produced by each letter individually. There are not many of these combinations, and they can be easily memorised. What is tricky is that several of them produce sounds which are foreign to the English language (and part of the French stereotype thanks to Peter Sellers and the Monty Pythons!).
Nasal sounds
Some teachers of French pronunciation try to teach these new sounds by finding English words that sound vaguely similar. Many of these are actually French words adopted by the English, and most often their pronunciation is so horribly butchered (especially by the Americans) that they are a useless teaching tool. I think of words like «Bon voyage» and «encore». So here is a little list of the letter groups and the sounds they should produce:
- in, ain, ein, un, im, aim, yn, ym:
- fin (end)
- nain (dwarf)
- plein (full)
- un (one)
- impression (impression)
- daim (fawn)
- lynx (lynx)
- lymphe (lymph)
- oin, oim:
- loin (far)
- on, om:
- bon (good)
- tomber (to fall)
- en, an, em, am:
- vendre (to sell)
- gant (glove)
- empêcher (to prevent)
- amphore (amphora)
The squiggle above the phonetic characters represents the nasalisation of the sound. Wikipedia has an excellent in-depth article on this subject.
Open vowels
This section is rather simple. In English it is possible to pronounce each of the vowels without hardly moving the mouth and the lips, and still be understood. In French this is not so.
The vowel ‘A’ must be pronounced by opening the jaw wide open.
The ‘O’ is pronounced by forming an ‘O’ with the lips.
The ‘I’ is done by almost closing the teeth, pushing the middle of the tongue against the palate and stretching the lips almost like a smile.
The ‘U’ is done by done just like the ‘O’ but the middle of the tongue must reach the palate, just as for the ‘I’.
The ‘E’ is simply half-way between the ‘O’ and the ‘U’: the tongue must reach half-way to the palate, but not touch it.
When forming your lips to pronounce the ‘O’, ‘E’ and ‘U’, make sure it is a very small ‘o’ you make. If it is too wide it will sound like ‘A’.
Another key concept with the vowels is that they form only one sound. English speakers tend to say: «Aw», «Ow», with a sort of deflation at the end. In French, all vowel sounds are constant: they sound the same throughout their pronunciation.
The Guttural R
This sound is so foreign to native English speakers that they often give up on adopting it, and settle for a «w» sound which betrays their anglo-saxon origin. True, it is difficult to train your mouth to produce a new sound on demand, but mastering the Guttural R is a skill well worth owning and honing.
The best way to learn it is to record oneself and to compare with the recording of a French person (or several). This is time-consuming, and can be very frustrating, but all true learning experiences are frustrating: the frustration is the stretch of the brain, the activation of new neural pathways. When you feel frustrated, try a little longer, then take some notes about your day’s efforts, and leave it all until later, possibly the next day. Don’t over-do it, we can only take so much brain-stretching each day 
