In my last posting, I said "成年后学外语，口音几乎不可能完全消除，略带外国口音不是坏事，但如果华人希望更好地与人交流、或从政、或跻身公司高层，减少口音即使不是必须的，也是有益的。它需要仔细听、模仿、学习，和长时间不懈的努力" (It is almost impossible to completely avoid having an accent if you learn a foreign language as an adult. A slight foreign accent is not a bad thing, but if you as a Chinese want to better communicate with people, take on a career in politics, or climb the corporate ladder, reducing the accent is beneficial, if not necessary. It requires careful listening, imitation, learning, and long hours of unremitting effort.) Honestly though, careful listening and imitation may not bring you forward as much as you want. But as an adult, if you're moderatly interested in linguistics, carefully studying International Phonetic Alphabet or IPA may benefit more. IPA has the ambition of recording with distinct symbols all sounds of all human languages in the world. But for us, we only need to focus on the sounds and symbols used in the English language for the purpose of improving English pronunciation. For example, if you have a hard time pronouncing bug as /bʌɡ/ and always, like many Chinese learners do, mispronounce it like /baɡ/ (where /a/ is the same sound as the vowel in Chinese character 爸), you can check vowel chart of IPA, and find where /a/ and /ʌ/ are. You can see that to move from /a/ to /ʌ/, all you need to do is move the location where the sound is produced back (toward the throat) and up a little. But a better description of this method is recently described in three online articles, which I highly recommend
IPA is not widely used in American education. Chinese learners may know some symbols to the extent of pronouncing the words by the symbols correctly most of the time. But the vowel and consonant charts are not part of the curriculum and so subtle differences between similar sounds are not fully grasped. The three articles above will hopefully make up for this deficiency.