Counting In Korean
Okay, so I get there are 2 systems of counting, Sino-Korean and the Chinese system, and I know how to count to 5 (ish... lol.). But I was watching Weekly Idol, and often they use "Ha" instead of "han-na" as 1, when they're saying 1! 2! 3! (하! 둘! 셋!). Is this just a shortening so it goes quicker, is it slang... I hear it a lot, especially when just saying, "one, two" and I don't hear Hanna as much.
하나 and 둘 are usually shortened to 한 and 두, respectively. Hearing that some people say "하" instead is truly odd to me.
I think they say 하 because 하 and 나 have anㅏsound, so they just say it as 하. Koreans also sometimes use the consanants ㄴ, ㄹ, and ㅇ like they are the same thing. You wouldn't say 하 for 1 when you're speaking formally, but maybe with your friends. This shortened word was probably invented by the teens and young adults. Hopefully that explains it.
I hadn't noticed this before you said it but I went back to watch some of the episodes and sometimes it does really sound like that. At first I was almost sure I heard 하나 but in the way they usually say it: "han" said super fast and "a" streched really long. But googling revealed that you're not the only one who has heard it. The best answer I was able to find is from Reddit Korean:
"It's 하나, but I know exactly what you're talking about. When native Koreans speak in a relaxed manner certain sounds are barely pronounced. I think a useful analogy might be the way cockneye (working class London) people pronounce "water". It sounds more like "wa'er" where the "t" doesn't sound. Anyone familiar with the accent recognises that this is simply how the word is pronounced in the accent, and similarly when you become familiar with certain Korean accents you will hear the slight, subtle flap of the tongue as a middle ㄴ.
There are other examples too. In the busan accent they often pronounce 먹어 more like 머어, with the ㄱ becoming almost imperceptibly subtle. There's no secret here, these are just peculiarities you'll have to familiarise yourself with."
"Yes, sometimes Koreans shorten the numbers when counting, so instead of 하나 둘 셋 넷 다섯 여섯, it can also be 하 둘 셋 넷 다 여"
Both of the comments taken from here: https://www.reddit.com/r/Korean/comments/6krsom/is_the_number_1_pronounced_%ED%95%98_or_%ED%95%98%EB%82%98/
Everything that HiNative has to offer seems to be two comments stating more or less that pronouncing it like that can be considered to be a mistake: https://hinative.com/ko/questions/3453215
I hope this helps :)
하나, 둘, 셋 i know this because of bangtan, lol.
But yes, they use mostly ha or at least that's what i hear...