Coming from a southern state in the US (Oklahoma) I feel that we owe the rest of the world an explanation over these two words; howdy and y'all

Howdy comes from the common greeting, "How are you doing" or "How do you do?". This was shortened into the word Howdy.

Howdy can still be used as a way to ask how one is doing, however it is more commonly just an informal way to say hello. You can often tell which meaning a person is using by how direct they are with you. For example, if you're passing by someone and they say, "Howdy" they're likely only saying hello an it would be appropriate to simply reply howdy back to them. However, if someone exclaims, "Howdy!" as they are approaching you then they are likely using it as an invitation for conversation. An appropriate response in this situation would be to let them know how you are then proceed to ask them how they're doing.

Y'all is simply a contraction or the shortened version of the phrase "you all".

Y'all originated in the Southern United States and is often associated with a very thick Southern accent. I'm sure most native language speakers who are not from a southern state read the word y'all with a southern accent in their heads without even realizing it. While in most cases stereotyping is frowned upon, it's actually kind of true here. Y'all is a very southern way of replacing the words "you all" or even "you guys".

I hope some people found this interesting and informative! Feel free to leave any feedback or your own opinions. If you're from a non-southern US state or even another country and you've heard either of these words being used then let me know!