Today in the USA, we are celebrating Mother's Day-so there's no better time for this sweet video.

It's the perfect day to meet Oswald, the 150-pound Colorado Rottweiler who loves talking to his mom-and anyone else who will listen.

Watch two-year-old 'Ozzy' becomes a teacher's assistant, stepping up to show his baby sister Amy how to say 'Mama'.

And check out the bonus video, which will melt any baby-lover's heart… Wallace giving his baby sister some snuggles.

SHARE the Sweet Moment With All the Mamas on Social Media…