Hair-raising gritos and "ay ay ay" chants from the cumbia circle aren't just background noise. They're part of what makes Fiesta, San Antonio's 11-day annual party, feel like a citywide family party.

Do you know that feeling when a song moves you so much, you just feel like you have to add your own voice? Mexican culture has an answer to that: a cathartic, joyous yell called a grito. Legendary ...