For He's a Jolly Good Fellow
"For He's a Jolly Good Fellow" was a Human song sung to celebrate significant milestones in an individual's life. 

In an alternate quantum reality, the crew of the  sang "For He's a Jolly Good Fellow" in Klingonese for Worf at his surprise birthday party in 2370. Counselor Deanna Troi translated it, but had problems as there was "no Klingon word for "jolly"." ()

It was sung when Benjamin Sisko was promoted from commander to captain in late 2371 and to Chief O'Brien on his birthday in 2373. ()

It was also sung to Kes on her ninth birthday in 2378 in an alternate timeline. ()

Lyrics 
For he's a jolly good fellow.
For he's a jolly good fellow.
For he's a jolly good fellow!
Which nobody can deny.
Which nobody can deny.
Which nobody can deny.
For he's a jolly good fellow.
Which nobody can deny.

Klingon translation 
cha wo'rIv toHgaHnaH lo pIre'toq
cha wo'rIv toHgaHnaH lo pIre'toq
cha wo'rIv toHgaHnaH lo pIre'toq
Tu Mak Dagh Cha doh Borak!

External link 
 

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Earth musical compositions