This is French carol translated into English by James Chadwick in the 19th century. We use the tune for Angels from the realms of glory, probably a better hymn.
Angels we have heard on high
Sweetly singing o'er the plains
And the mountains in reply
Echoing their joyous strains
Angels we have heard on high
Sweetly, sweetly through the night
And the mountains in reply
Echoing their brief delight
Gloria, in excelsis Deo
Gloria, in excelsis Deo
Shepherds, why this jubilee?
Why your joyous strains prolong?
What the gladsome tidings be
Which inspire your heavenly song?
Gloria, in excelsis Deo
Gloria, in excelsis Deo
Come to Bethlehem and see
Him whose birth the angels sing,
Come, adore on bended knee,
Christ the Lord, the newborn King.
Gloria, in excelsis Deo
Gloria, in excelsis Deo
See Him in a manger laid,
Whom the choirs of angels praise;
Mary, Joseph, lend your aid,
While our hearts in love we raise.
Gloria, in excelsis Deo
While our hearts in love we raise, etc
I have versions by Page CXVI and The Roches.
Other verses
Shepherds in the field abiding,
Tell us when the seraph bright
Greeted you with wondrous tiding,
What you saw and heard that night.
Refrain
We beheld—it is no fable—
God incarnate, King of bliss,
Swathed and cradled in a stable,
And the angel strain was this:
Refrain
Choristers on high were singing
Jesus and His virgin birth,
Heavenly bells the while a-ringing
Peace, good will to men on earth.
Refrain
