The IPA is a pretty good invention, allowing us to transcribe languages with as much precision as we feel is necessary. It's especially useful for language learners, as each IPA character's name is basically an instruction on how to pronounce it. However, you should be careful when it comes to the IPA, because a transcription is not always reality!
To start with a trivial example, consider that the General American English rhotic sound is represented as /r/ in most transcriptions, even though it is not an alveolar trill in any variant. This is for reasons of tradition, convenience ('r' is easier to type than 'ɻ'), and generalization ([ɻ] is not the only realization of the American rhotic, and 'r' is a suitable enough symbol for the rhotic). I doubt anyone has been misled to believe that American English uses an alveolar trill, but it serves as an example of this disconnect between map and territory.
All this to say, if you are trying to learn a new language, it is not enough to just read IPA transcriptions. Practice listening closely to the language.
For example, most IPA transcriptions of Russian /o/ are [o]. If you try to learn Russian pronunciation by referencing a table like this (as I know many autodidacts on the internet do), you may think that Russian has a monophthongal [o] sound, much like Spanish.
| Front | Central | Back | |
|---|---|---|---|
| Close | i | (ɨ) | u |
| Mid | e | o | |
| Open | a |
(Table from Wikipedia page on Russian phonology)
It is true that Russian [o] may be monophthongal, but Russian [o] is also often diphthongized! I had noticed this for years in listening to Russian, but it was only by looking up 'Russian o diphthong' and talking to Russian-speaking linguists that I found any sources on it. You'll definitely not find anything on it in beginner textbooks on Russian.
The /o/ vowel is a diphthongoid, with a closer lip rounding at the beginning of the vowel that gets progressively weaker [ᶷo] or even [ᶷɔᶺ], particularly when occurring word-initially or word-finally under the stress, e.g. očen' [ˈᶷoˑt͡ʃjɪn̠ʲ] ‘very’, okna [ˈᶷɔᶺkn̪ə] ‘windows’, moloko [məɫ̪ʌˈkᶷɔᶺ] ‘milk’.
(2015) "Illustrations of the IPA", Yanushevskaya and Bunčić. h/t to prikaz_da
The Swedish sj-sound is a drastic case of IPA misleading. If you have ever heard that the sj-sound is a 'coarticulation of [ʃ] and [x]', you may be entitled to financial compensation! Or at least, linguistic compensation, because it is not actually a coarticulation of [ʃ] and [x]. It's often something much simpler - a voiceless 'wh' [ʍ] (like in Southern American English), a labialized [xʷ], a [ʃ] or [ɕ]. Lindblad even offers up a velarized and labialized labiodental [fˠʷ] as a more likely pronunciation. The video below demonstrates:
I was never able to 'coarticulate' [ʃ] and [x], but a Swedish native speaker once told me that I had a pretty good approximation of 'sj'-sound. My approximation was based not off reading IPA descriptions but off listening to Swedish. I ended up doing something like [çʷ] or [xʷ], because that was what I heard.
This does not mean you shouldn't ever use the IPA a guide. Don't take broad IPA transcriptions as the final word, especially if you are just seeing a table of phonemes. If you notice that you hear something that does not seem to be in the standard IPA transcription, trust your ears! Look for articles on the phonetics of that sound if you can. Many descriptions of languages are old, or put together by someone on Wikipedia, and while there are many great Wikipedia editors, they may make mistakes or omit information for brevity's sake.
I'll finish with a quote from one of my phonetics professors - "write what you heard, not what you think you heard." What are some examples of pronunciations you've noticed that don't match common descriptions of the language?
