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
At a British birthday party, the traditional song typically performed is "Happy Birthday to You." This song is often sung to celebrate the birthday of the individual, and it has become a staple at gatherings. In some regions, variations of the song may be sung, but "Happy Birthday" remains the most recognized and widely used.
"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.
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.
Probably "Happy Birthday to You".
Happy Birthday, if it is being sung to someone called "Word Of Mouth".
The song is La Golondrina and there is a video clip from the film with the song on youtube along with other versions.