Here is a link to the lyrics and MIDI. Who could ask for more?
I found the lyrics at this site and another. both say "like a morning spring," and my songbook says "like a morn in spring," which makes more sense.
Although it ain't what I'd call folk, here are the lyrics:

When Irish Eyes Are Smiling
Music by Ernest R. Ball
Words by Chauncey Olcott & George Graff, Jr.
(copyright claimed in 1994 by Hal Leonard - yeah, sure...)

When Irish eyes are smiling
Sure it's like a morn in spring.
In the lilt of Irish laughter,
You can hear the angels sing.
When Irish hearts are happy,
All the world seems bright and gay.
And when Irish eyes are smiling,
Sure, they steal your heart away.

-Joe Offer-