The International Phonetic Alphabet is supposed to have a specific symbol for every sound in every language. But when you look closely, there seem to be some discrepancies.
I have lived in France for forty years and speak French fluently, so let’s compare the way IPA sound symbols are used in English and French.
In English, there is a sound designated by the IPA symbol ə (called a schwa), found in words like the. There is also a sound designated by the IPA symbol r found in words like red.
In French a similar but different sound is designated by the IPA symbol ə, found in words like le. There is also a similar but different sound designated by the IPA symbol r found in words like rouge.
In English, the symbol ʌ is used to designate the sound used in words like sun. In French, the IPA symbol ɑ is used to designate the sound in words like Paris. I can’t honestly say there is any difference between these two sounds. Furthermore, in English, to designate the long-a sound as in the word palm, the IPA symbols ɑː are used together, with the ː indicating that the a-sound is long, which seems to suggest that if it were short then just the ɑ would do. But no.
Also, as the French have bagged the letters o, y and a, the English can’t use them in their IPA symbol set.
It’s the good old
Common Market European Union situation as usual, where the diffident Brits bend over backwards to obey the rules and the French do whatever they feel like.
In short, the IPA system as used for English reflects a lot of compromises that make it unwieldy, and it is not even really an international system.
I am helping my Chinese wife learn French, and this is what I noticed in her text book (click the picture to embiggen it). In the top row you can see that the schwa is specified for the pronunciation of the French words se, le, te and ne. Here the sound is not the same as that designated by the schwa in English transliterations.