QUESTION: Why are there different phonetic symbols for the same sounds? Which ones should I learn?
ANSWER: First of all, I don’t think it’s absolutely necessary for students to learn the IPA or any other set of phonetic symbols in order to master English pronunciation. However, I do think that familiarity with the symbols is helpful since they appear in dictionaries and other language resources. Being able to recognize phonetic symbols increases a learner’s independence when faced with a new word and its pronunciation. Knowing the symbols can also heighten a learner’s awareness of individual sounds. Seeing, for example, that “it” and “eat” require different symbols confirms that the short “i” and the long “e” are indeed two distinct sounds and not the same.
As a way of explaining the fact that different symbols exist for the same sounds, it might be simplest to draw a comparison: just as spelling variations have evolved in different varieties of English (e.g., theater v. theatre), so too have different phonetic symbols. One is not superior to another. In both cases, the important thing is to be consistent in one’s writing yet flexible when reading. I’ve taken this stance before with regard to varieties in pronunciation, and I argued for consistency in production and flexibility in comprehension.
If you are able to choose which set of symbols to present to a learner or group of learners, you might consider what best suits their needs. Linda Lane points out that /ay/ and /ai/ both refer to the long “i” in “time”, but for some students who do not clearly produce the glide ending in this dipthong, seeing the symbol /ay/ might be more effective in correcting the error. The understanding that /y/ is needed to join the first and second vowel sounds is important (Lane 191).
Reference:
Lane, Linda. (2010). Tips for teaching pronunciation: a practical approach. White Plains, NY: Pearson Longman


