Simplify the following text for a Grade 11 native English-speaking person.
Original: In My First Signs , it was not originally planned for Rachel to be in the videos , but she was added to demonstrate the signs because Alex and Leah ( then 3 and 4 , respectively ) could not consistently sign clearly enough to teach viewers the signs .
Simplified: In My First Signs , Rachel was not going to be in the videos , but she was added to show the signs because Alex and Leah ( who were 3 and 4 then ) could not sign clearly enough all the time to teach viewers the signs .