Get from Single Words to Sentences using Core Words (Part I)

I started seeing a child a few weeks ago who was stuck in the “I want” phrase, unable to say anything else. Mom was trying to teach her basic verbs (e.g. “eating, running, drinking,”) but she was adding the “I want” phrase to EVERYTHING so that when she was putting words together and it didn't always make sense.  

When children reach a plateau like this, and are unable to put words together into phrases or sentences, this is always when I start thinking CORE WORDS.