All the lyrics are written by her and based upon herself and the people around her.
I think they depend on the seasons also, as Inspire had a summer feeling with the dancing and the beach and all (refer to her PV)...
Carols will probably have a Christmassy or Autumn feeling with the instruments used... but don't know yet...
(No Way To Say was released around this time... and I think it will have something like this...)