Answer:
I am the word that is always spelled correctly by everyone.
Send poorly behaved children to me and let them sit here.
Whoever made me doesn't want me. Whoever bought me doesn't need me. Whoever uses me doesn't know me. What am I?
When you need me, you must find me. When you find me, you no longer need me. What am I?
You use a knife to slice my head and weep beside me when I am dead.
Give it food and it will live, give it water and it will die.