As a non native english speaker, I'm trying to work on my accent. I've taken a lot of bad habits so I'm trying to go back to the fundamentals meaning learning phonetics. But they seem very imprecise to me. For example the word hand.
https://dictionary.cambridge.org/dictionary/english/hand
Here the UK seems to pronounce the æ like it's really a single sound and the USA pronounce it more like two sounds: starting like hen then joing the ~ha sound. With such a big emphasis on the hen sound that if the word were pronounced quicker I think I would have heard it as hen with a d.
Now if I trust what I hear here, the USA seems to be right.
But this pronunciation seems to be very, very inconsistent. The word cat (same phonetics):
https://dictionary.cambridge.org/dictionary/english/cat
Here we have the same kind of pronunciation variation but "reversed". The USA cat is closer to the UK's than the USA hand but we can still hear a little hen sound at the beginning.
Now, worse : trap
https://dictionary.cambridge.org/dictionary/english/trap
Here the UK and the USA are strongly agreeing on disagreeing with the IPA pronunciation of æ pronunciation I linked before.
So, why two clearly different pronunciations have the same phonetics symbols ?
Why the same phonetic symbol can be pronounced so differently from a word to another within the same "accent" ?
Are phonetics simply unreliable and should only be used to know roughly how a word should be pronounced ?
Would the most effective method to be sure I pronounce a word correctly be to search on internet for video or audio samples of people pronoucing them in context ?