Possible Clues:

• 1973 hit that begins "Como una promesa"
• Mocedades hit of 1974
• Spanish for "you are"
• 1974 hit with a Spanish title meaning 'You are'
• 1974 top 10 foreign-language hit
• Title words repeated after "Como una promesa," in a 1974 song
• 1974 top-10 hit with Spanish lyrics
• 1974 Mocedades hit whose English version is titled 'Touch the Wind'
• 1974 Top 10 hit whose title means "You are"
• 1974 hit with a Spanish title