VIDEO: Big sister's music teaches toddler with Down syndrome to talk

UTAH -- It's a touching moment between two siblings that's sending a wave of smiles across the internet.

The moment was shared between Lydia Gray and her youngest brother, Bo.

Bo is just 25 months old, has Down syndrome, and suffers from a long list of medical ailments.

Bo can't speak many words, but he can sing them. And as the video above shows, he LOVES to!

Bo's mom and dad started singing to him as he recovered from several tough surgeries and immediately saw him responding.

They say every word he knows - all 12 of them - he learned through songs. Bo's very first word was "happy."

They also say it's not just the lyrics, but the love with which they are delivered.