Her back story and appearance is very similar to the story The Little Match Girl, written by Hans Christian Andersen (author of The Little Mermaid). As the story goes, the little girl sells matches on the side of the road in the freezing cold weather. She can't go home, because she is afraid her father will beat her for not selling enough matches. So she huddles her little body up and tries to stay warm. She ends up lighting the matches and seeing amazing visions of food and her departed grandmother. She ends up using all the matches before the end of the night, and her little limp body is found in the morning.
Sofie's story also has similarities to the Bobby Darin song Artificial Flowers, which is about a little flower seller, who didn't make it through the cold winter's night.
PC 360 PS3 Sometimes, when the Dragonborn chooses to adopt Sofie, if they are living in Lakeview Manor (Falkreath), Sofie will say that she will collect her things and meet them at the house, however she will remain at place and not move. If she is approached again, she repeats that she is collecting her things but does not move anyway. To fix this, another home with the children's bedroom improvement is needed. Approach Sofie and tell her to go there. Find her there and tell her to move to Lakeside Manor, she will appear there after some time, normally.
PS3 PC Sometimes, when the Dragonborn chooses to adopt Sofie, if they are living in Honeyside (Riften) Sofie will say that she will collect her things and meet them at the house, however she will remain in Windhelm. If she is approached again, she will say "I...I have a home again. A family. I almost can't believe it".
A possible fix is to tell your wife/husband to move to another home. you will not be able to tell Sofie directly, she will just keep saying "I...I have a home again. A family. I almost can't believe it".
Even if Sofie moves into your home after telling your wife/husband to move somewhere else you may still be unable to click on her to talk, give gifts or whatever, but she does start acting normal, making comments about her new home and the people around.
PC 360 Sometimes, after she has been adopted, it is impossible to give her gifts like dresses, dolls or wooden swords. It would appear this has something to do with her old trader status, she may be keeping her shop inventory as her own inventory. As this includes an increasing number of baskets, this makes her overencumbered, causing the message "the gift is too heavy to carry" to appear. It seems the only way to prevent this is by buying all of her baskets before adoption.
PC It is possible to use the console command "removeallitems" to remove everything in Sofie's inventory after adoption. She is then available to give items and receive the "The Gift of Charity".
Sometimes, after adopting her, Sofie can be seen running around the town with no clothes on, and all of her clothes are in her chest. To fix this, retrieve the dresses, and give them to her. She should then re-equip the dress.
360 Sometimes she will refer to a female Dragonborn as "Pa"