Using 말이야 naturally
I think I understand what it means, if I'm correct 말이야 means "you know"
But I'm very confused how to use it naturally, I hear it so often but still
am not clear what kind of situations I should use it in. Is it a phrase that can
be used in various situations as well? I always hear it in songs as well.

Could someone explain it for me and give a few examples to demonstrate how its used?

Much appreciated!

Question

Using 말이야 naturally
I think I understand what it means, if I'm correct 말이야 means "you know"
But I'm very confused how to use it naturally, I hear it so often but still
am not clear what kind of situations I should use it in. Is it a phrase that can
be used in various situations as well? I always hear it in songs as well.

Could someone explain it for me and give a few examples to demonstrate how its used?

Much appreciated!

Answer

This phrase usually used for these reasons or situations:
1) to be sure someone is listening carefully and agrees with what you are saying. For example: It didn't have to happen that way, you know?
2) An expression placed on the end of a statement for pause or emphasis. Example: Sure, I spent a fortune on this car. Can't take it with you, you know.
3) You actually start a sentence with "You know," when you want to give someone information that you think they don't know.

Answer

This is really helpful, thanks!

Answer

Generally, it's used as a highlight in the conversation. 
 
You can omit "말이야". It's a kind of two different sentences.

" 지연이 (말이야), 이번 여름에 유럽으로 배낭여행 간다더라."
(You know what, Jiyeon is going to go backpacking to Europe this summer.)

"  내 말은 (말이야), 서진이가 우릴 생일파티에 초대했다는 거야. "
(I mean, Seojin invited us to his birthday party)

Meanwhile, in this case, you cannot omit it in the sentence. They're all single sentence.

" 딸기 케이크가 정말 맛있단 말이야.
( You know, the strawberry cake is really delicious! )
 
" 그냥 집에 있을래. 정말 피곤하단 말이야. " 
(I'll just stay at home. You know, I'm so tired.)