Using 「呟く」 while speaking with someone else


Following Mindful suggestion
[here](https://japanese.stackexchange.com/a/77000/35362), I'm opening this
question following that one: in there, Mindful explained that the main
difference between 「つぶやく」 and 「ささやく」 is that, I quote:

> you want 囁く when you are talking about whispering something to someone. 呟く
> on the other hand is also often translated as mumble or mutter, English
> words which better express the idea that the thing being said is not
> intended to be heard by anyone but the speaker

My doubt arises from short stories I'm reading, in which 「つぶやく」 is used when a
character is speaking with another, seemingly with the intention of being
heard, and the other characters seems to hear it:

> 彼女が困ったように視線を地面に走らせながら、
>
> 「あの、家まで送ってくれない？こんな遅くまで働いたことはなかったから」と小さな声で **つぶやいた** 。
>
> 「ああ、そうかー」
>
> 僕はアルバイトのシフトに入るとき、彼女が必ず「早番」の時間帯を選ぶことを思い出した。

In this case the girl is asking the protagonist to walk her home, and it
doesn't seem she doesn't want to be heard; the character does hear her.

So I was wondering: does this have any implications about the speaker not
wanting to be heard, or 「つぶやく」 can just be used to speak to others?

Edit: a little more context: as far as I can understand the only relationship
between them is professional, both work at the same restaurant; a little later
on she says that she always asks for early shifts because she is afraid of the
night (夜がー怖いから), but that day she had to stay until late, so the request to be
walked home seems to be honest, not just a front to keep the relationship.
Here's the page: <https://i.stack.imgur.com/FNXjg.jpg>.




> 「つぶやく」 can just be used to speak to others

I would say this is the answer of you.

However, "つぶやく" certainly has a meaning to speak to oneself. It's like the
speaker doesn't matter if someone hear what he/she says or not.  
This may be the key to get mind of the girl. She asked him but these lines of
dialogue were not articulated clearly. She wouldn't matter if the request is
rejected, or even if it's not heard by him. She carefully and indirectly asked
to keep current relation with him(Japanese-style?).  
This is my impression after reading the text.

By the way, if you use "ささやく" in this context, the story would drastically be
changed!!! I believe most of Japanese think the girl is tempting him!!!




> 「つぶやく」 can just be used to speak to others

I would say this is the answer of you.

However, "つぶやく" certainly has a meaning to speak to oneself. It's like the
speaker doesn't matter if someone hear what he/she says or not.  
This may be the key to get mind of the girl. She asked him but these lines of
dialogue were not articulated clearly. She wouldn't matter if the request is
rejected, or even if it's not heard by him. She carefully and indirectly asked
to keep current relation with him(Japanese-style?).  
This is my impression after reading the text.

By the way, if you use "ささやく" in this context, the story would drastically be
changed!!! I believe most of Japanese think the girl is tempting him!!!

