What is when a girl says a friend vs my friend?

When a girl says "a friend," she could be referring to any person in her life who she considers a friend, whether male or female, without any particular significance attached to that person. It could be someone she met recently or someone she has known for a long time.

On the other hand, when a girl says "my friend," it typically implies a closer relationship and a sense of ownership or possession over the friendship. It usually means someone with whom she shares a strong bond and has a special connection with. The use of "my" suggests that this friend is important and significant to her.

In summary, "a friend" is a more general and neutral reference to any person considered a friend, whereas "my friend" implies a closer, more personal relationship.