From U2log.com:
"U2 kicked off the fourth leg of their Vertigo tour in the Mexican city of Monterrey yesterday (Feb. 12). 48 hours before the concert, more than 600 fans were sleeping at the gates of the stadium in order to get into the ellipse; 24 hours before the show, there were more than 2,000 fans. Mexicans have really missed the band, since the last time U2 visited Mexico was during the PopMart tour in 1997.
Bono spoke in Spanish several times during the concert. Before “One,” he said to the audience: “La gente dice que no se puede cambiar al mundo, que tu no puedes, que yo no puedo, The Edge no puede, pero si se puede, si actuamos todos como UNO.” Translation: “People say you can’t change the world. You can’t, I can’t, The Edge can’t…but it is possible if all we act like ONE.”
One surprise during the show was a snippet of the traditional folk song “Cielito Lindo” during “Bad.” Other highlights include Bono pulling two girls on stage for “Miss Sarajevo,” and another one during “With or Without You.”
Cielito Lindo
Quirino Mendoza y Cortés, ~1859-1957
De la Sierra Morena,
Cielito lindo, vienen bajando
Un par de ojitos negros,
Cielito lindo, de contrabando
Coro:
Ay, ay, ay, ay,
Canta y no llores,
Porque cantando se alegran,
Cielito lindo, los corazones
Pajaro que abandona,
Cielito lindo, su primer nido,
Si lo encuentra ocupado,
Cielito lindo, bien merecido
Coro:
Ese lunar que tienes,
Cielito lindo, junto a la boca,
No se lo des a nadie,
Cielito lindo que a mi me toca
Coro:
Si tu boquita, morena,
Fuera de azucar, fuera de azucar,
Yo me lo pasaría,
Cielito lindo, chupa que chupa.
Coro:
De tu casa a la mía,
Cielito lindo, no hay más que un paso,
Ahora que estamos solos,
Cielito lindo, dame un abrazo.
Coro
-----------------------------------------------------------------------
Hope this helps answer the questions about Bono speaking (and singing) in Spanish last night.