Here's why:
* It's a noun phrase. It refers to two people, Ellen and the person being addressed.
* It needs a verb. For example: "Ellen and you are invited to the party."
Here are some examples of how "Ellen and you" could be used in a sentence:
* "Ellen and you should meet for coffee sometime." (This is a suggestion)
* "The store is closed, so Ellen and you will have to come back tomorrow." (This is a statement)
* "Did Ellen and you enjoy the movie?" (This is a question)
Let me know if you have another phrase you want to check!