Some languages, such an English and German, make a distinction between the aspirated voiced consonants
tʰ on the one hand and the unaspirated voiced
d on the other.
Standard Chinese by contrast, makes a distinction between the aspirated voiced
tʰ on the one hand and the unaspirated
t on the other. Native speakers of English and German are not used to the unaspirated
t at the beginning of a word and when speaking Chinese tend to replace them with the aspirated
d, respectively, especially since Hanyu Pinyin represents these sounds as "b" and "d" in spelling.
How do you teach the correct pronunciation of words such as "bàba" (with unaspirated
p) and "guāndiǎn" (with unaspirated
t in the second syllable)?