While several people have asked about the pronunciation difference between じ and ぢ(there is none), the difference between ち and ぢ has not been talked about much. Yet, they seem the same to me, even though their Romaji is different. The pronunciation of ち is like the English letter 'j' (as in judge) and so is the pronunciation for ぢ.
I am confused about the pronunciation difference between 'chi' and 'ji'.