LO is almost 14 months and has been using signs for a while now, and started with some words. Still, sometimes he can't seem to help but whine whine whine when he wants more food, or is all done, etc.

Right now we usually ask him to sign or say the word, and demonstrate ourselves, and then ask again, and then give up. I'm curious what age people started implementing tactics like "I don't understand you if you're whining"?