Things that happen when you have teenagers and a toddler

Lately Kenna has been picking up words from Josh and Kayla I am not talking about nasty words we don't say them in our house. I'm talking about teenage talk. Kenna has been going around with her cell phone saying I'm texting one minute. When I ask her to do something she says I am like her sister Kayla always says.The other day she looked at me and said my bad. How can you keep from laughing at her. She uses three and four word sentences now. She just 2 years old going on 15.