What is that sound?

Hey!
What is that sound?
Why...it's Jonah and I singing one of our favorite songs to Grandma!
Can you guess what it is?

"Happy Birthday to you,
Happy Birthday to you,
Happy Birthday, Dear Grandma!
Happy Birthday to YOU!!!"

Today is Grandma's Birthday and we wanted to wish her
a wonderful day and safe trip back from your mini-vacation.

We love you, Grandma!
Have a wonderful Birthday.