I think you may be referring to "Las Mananitas" (pronounced mah-niah-nee-tas), a traditional birthday song. There is also the Spanish rendition of "Happy Birthday" that is sung at the end of "Las Mananitas".
spanish
"La Bamba"
Happy birthday
The Japanese Happy Birthday song is sung the same way it is sung in English but in Japanese's translation. Even in most Japanese schools they also sing it in English version as well.
Happy Birthday
One of the songs that is sung by Roberto Orellana is the song Mi Nuevo Amor. Another of the songs that is sung by him is the Spanish song Mi Sagrado Ricon.
ummmmm
Supposedly it's "Happy Birthday"
There are many versions of the Happy Birthday song. There is the American version, which most people know. Prior to the 1900s, people also sung, "For He's A Jolly Good Fellow", for men celebrating their birthday. In France, the song is called, "Bon Anniversaire", and is sung to the same tune as the American version.
Happy Birthday, if it is being sung to someone called "Word Of Mouth".
Probably "Happy Birthday to You".
The song is La Golondrina and there is a video clip from the film with the song on youtube along with other versions.