初めて聞いたよ

I've never heard that before

→ 初めて
phrase Rare #39,719
I've never heard that before The ending よ adds emphasis, making the statement sound conversational.
JA: その映画のことは初めて聞いたよ。
EN: I've never heard of that movie before.

この単語は初めて聞いたよ。

I've never heard this word before.

そんな話初めて聞いたよ

That's the first time I've heard that.

— マルホランド・ドライブ (2001)

お前のあんな話し方、初めて聞いたよ。

I've never heard you talk like that before.