What is the main reason that attitudes are more often revealed in spoken rather then written language?

There is really no possible way to completely express how you are feeling or your attitude on something by writing it out. 

Doulingo is good. you can also watch movies that are in french, i am using this tactic  for japanese  and it a lot. listing to music with  french  lyrics would work well too because  you could absorb  the words while having fun.hope this ! : )