~たいだとか why is there a だ here?

Question

軽々しく死にたいだとか

愛を伝えたいだとか

I found these from some songs. If たい is considered an I-adj then I wonder why it's だとか instead of とか.

Answer 1

だ between a verb/i-adjective and と/とか/なんて/etc adds an accusatory and/or shocked tone. In this case, this だ implies words like 死にたい and 愛を伝えたい are inappropriate because they are 軽々しい.

From 明鏡国語辞典:

だ

❹ 《「…━と」「…━って」「…━なんて」の形で》不適切と思われる相手の言葉を直接引用して示す。多く、非難・意外などの気持ちがこもる。
「なに、行きたくない━と」「参加しない━なんて言わないで…」

It's even used like an accusatory sentence-end particle (masculine and rough, mainly in fiction):

• はあ、怖いだぁ？ Huh? (Are you saying) are you afraid?
• 何、知っていただ？ What? D'you say you knew this?

Related:

• Is 「３人いるだと」 grammatical?
• what does としてもだ mean in this sentence?

Bonus:

It's also possible to say "verb + ですって?":

• えっ、3人いるですって? Eh, (you said) there are three people!?
• 宿題を忘れたですって?
• 静かにしろですって? Do you (really) want me to shut up?

Answer 2

〜だとか and 〜とか are really similar meaning. Actually you can use 軽々しく死にたいとか instead of 軽々しく死にたいだとか. If I were to say something like this:

彼は軽々しく「死にたい」とか言っていた
（I don't feel anything about the word "死にたい" and him）

彼は軽々しく「死にたい」だとか言っていた
(I don't like the word 死にたい or the fact he said 死にたい, I am thinking he shouldn't say such a things)

However...

Yu-chan said "wanna quit the job".
優ちゃん「仕事やめたい」とか言ってた！

If someone said this sentence anxiously, I'd feel the person didn't want her to do so. In speech we usually use ~とか like this: someone said something and I wanna say the words.

If my friends told me 優ちゃん「仕事やめたい」だとか言ってた！ I'd feel something was wrong.

優ちゃん「仕事やめたい」とか言ってた！is more naturally.

And another situation: we use it for rumor.

噂によると、彼はお金持ちだとか・・・
According to the rumor, he is rich...

I don't know if he is rich or not.

Someone said something but I don't know if it is true or not.

友達に聞いたんだけど、Aは死にたいって言っただとか.
I heard from my friend that A said "wanna die".

I hear from my friend but I don't know if it is true or not. In this case, you can change ~だとか to ~らしい.

噂によると、彼はお金持ちらしい。

友達に聞いたんだけど、Aは死にたいっていったらしい.

and sometimes we say 行ったんだとか with the same meaning as 行っただとか.