People move on. Most players I know got bored of the game itself or just wanted to try something new, i'm sure it will happen to you also. I have actually seen lots more players joining the game recently, these players will then play for a short/long period of time, then they might quit. That's how games work. When people saying games are 'dying' that's when they lose the cycle and you don't have any new players.
The word holla is in the English dictionary but with a different meaning from the way it is used today. It originally meant stop or halt but that use is now obsolete. In the US, holla is now slang for the word holler which means to shout or yell. However, as with most slang words, it is not something everyone knows or uses. You may even notice that when you type it here on the forums it is underlined in red meaning that it's not recognized as valid word. Nobody should be shamed for not knowing slang, especially when it's from another country.
I'm sorry, I didn't mean to sound rude. I guess I was just referring to people I've met in-game, and it bugs me a lot. Nvm, not important. The point is, I wasn't directing that towards you. Sorry for any inconveniences.