What's the meaning of self-deficiency?

[tulipflower]

Oh, I’m so sorry! I didn’t see your bag- I hope nothing’s broken

Among different strategies for apologizing, one is an acknowledgement of responsibility.
one way to acknowledge the responsibility is 'expressing self deficiency' like ''I didn’t see your bag' in the aforementioned sentence. I can't get the meaning ofself deficiency. What does it mean?

[Rover_KE]

Source and author?

[emsr2d2]

Oh, I’m so sorry! I didn’t see your bag. I hope nothing’s broken.

Among different strategies for apologizing, one is an acknowledgement of responsibility.
​One way to acknowledge the responsibility is 'expressing self-deficiency' like ''I didn’t see your bag" in the aforementioned sentence. I can't get the meaning of self-deficiency. What does it mean?

It means that you acknowledge that you made an error. You are acknowledging that it is, to some extent, your fault. A "deficiency" is a sort of failure.

[tulipflower]

Source and author?

"Apology: a speech act" written by Olshtain and Cohen (1983). It's an article.

[emsr2d2]

Please remember to state the source and author in post 1 in future.