I'm interested in phonetics in order to speak as properly as possible. And here's the thing, there are four vowels with ambiguous symbols:
The first problem is the sound [ɛ] like in dress: /drɛs/ according to WordReference and Oxford dictionary but [e] like in dress: /dres/ according to Cambridge dictionary. So I've made some research and the only reason I've found so far is from teflpedia:
The English phonemes /e/ and /eə/ use "e" instead of "ɛ" only for historical reasons, and several dictionaries prefer "ɛ" over "e".
What are these historical reasons? And why do they continue to use [e] instead of [ɛ]? Because first in French we use [e] for the sound 'é' like in fiancé which is a different sound. It is a weird behavior because their table shows that the majority of dictionaries tend to use [ɛ] so why do they keep going on this way? TEFL stands for Teaching English as a Foreign Language not Confusing Foreigner, doesn't it?
The second problem is [a] instead of [æ]. In the word cat: /kæt/ according to Cambridge and wordreference but /kat/ according to Oxford. Is there another historical reason here?
The third problem is between [ə:] and [ɜ:]. In the word bird Oxford says /bəːd/ and Cambridge and wordreference say /bɜːd/. Which one is the correct one?
The fourth problem is between [eə], [ɛː] and [ɛə]. In the word bear Cambridge writes /beər/, Oxford writes /bɛː/ and WordReference writes /bɛə/. It is seriously confusing!
Thank you if you have any explanation.