The letters in the Pinyin is confusing. How do you differentiate a B w/ P? How do you differentiate a T and D?

How do you differentiate a B w/ P? How do you differentiate a T w/ D? How do you differentiate a Q w/ J? Is there a rule for these?

There is a good resource available from MIT Open Courseware: an online Chinese textbook. This includes details on Pinyin pronunciation, including audio files. I still am probably missing a lot of the subtleties but the audio files help. http://ocw.mit.edu/resources/res-21f-003-learning-chinese-a-foundation-course-in-mandarin-spring-2011/online-textbook/part-i-introduction-units-1-4-character-lessons-1-3/ The book has the following explanation on page 23: In English, the distinction between sounds such as ‘b’ and ‘p’ or ‘d’ and ‘t’ is usually said to be one of voicing (vocal chord vibration): with ‘b’ and ‘d’, voicing begins relatively earlier than with ‘p’ and ‘t’. However, in Chinese, the onset of voicing of the row I consonants is different from that of English. The sound of pinyin ‘b’ is actually between English ‘b’ and ‘p’, that of pinyin ‘d’, between English ‘d’ and ‘t’, etc. That is why the Wade-Giles system of Romanization (mentioned in the introduction) writes ‘p/p’’ rather than ‘b’ and ‘p’ (T’aipei rather than Taibei); in phonetic terms, both are voiceless, but the first is unaspirated, the second aspirated. Being aware of this will help you to adjust to what you hear; and remembering to articulate the column I initials ‘lightly’ should keep you from sounding too foreign.