Ok i have few minutes.
HOW TO MODIFY THE MAPPING FOR BEGINNERS:
step 1 download Notepad++ from here
You must be registered to see the links
( i suggest the 64 bit version )
step 2 install Notepad++
step 3 locate the mapping file you want to modify, select it and make a backup copy of it.
step 4 open Notepad++ and click on File ( top left ) then click on open, search and select the file you need to modify and click on Open
step 5 select the text you need to edit ex : mate and change it to sister or landlady and change it to mom, is very intuitive trust me.
DO NOT change any value or line that is not the name or nickname of the character
step 6 save and DO NOT click on save as JUST SAVE.
JOB DONE or so it should. this also work for every XML file. i'm sure that somewhere on this site there is a guide similar to this but hitting search bother me so i wrote a new one.
IMPORTANT
P.S. if the file is too complex or too long to find ALL the values you want to modify, just wait for a patch made by some modder, as an XML file wrongly modified can crash the game.