What does volitional form + っと mean?

Question

「そうだ！家で音楽聞こうっと」

「もう寝ようっと」

「英語でブログを書いてみようっと。」

How does it differ from a volitional form without っと?

My best guess is that it's a monologue marker, like な is.

Answer 1

Yes it's a sentence-ending particle which is usually used in monologues. One article says the main function of this っと is to casually convince/confirm something to the speaker themselves. Perhaps it's like saying 'okay' to yourself.

• これで良しっと。
• 今日も1日お疲れさまでしたっと。 (before going to bed, to oneself)

Occasionally it's used when there's an actual listener. When that happens, it expresses the speaker's sarcasm or indifference to the matter or the listener.

• 俺はもう知らないっと。 I don't care any more.
• 「彼女ができたんだ。」「そりゃよかったねっと。」 (indifferently)

Answer 2

I might be wrong, but it sounds to me like a shortened version of と思います, something like "I think I will...".

「英語でブログを書いてみようと思いました。」

I thought about writing a blog in English.