My mother was a stickler for proper speech and tirelessly corrected my siblings and me until we pretty much knew the rules by rote.
As she used to tell us: "People won't necessarily notice when you speak correctly, but they'll notice it when you don't."
This is especially valuable advice in situations such as job interviews and speeches/presentations to large crowds.
LOL. Almost sounds like we had the same mother. My brothers & I used to HATE those corrections, but looking back on it today (I am 41) I'm SO grateful that she did.
Have a nice weekend!
Pete