I polled my son on the most important words in English. He deliberated some time and then offered me the following list:

Blocks

Ball

Book

Mama

Cat

Dada

Walk

Run

Hi

Bye

Tree

Rain

Snowman

Water

Chair

Cheese

Banana

Apple

Help

Up

Cracker

Puppy

Love

Hug

Bean

Bear

Bath

All animal sounds, and, especially, roaring.