'Cuba Si!' by Terrance McNally is an interesting piece. I saw an excerpt judging a competition recently, and it was a very intense, comic piece. Not entirely Spanish language, though there is some Spanish in it. Might not be appropriate for public performance at the high school level, but it could be a very interesting piece to do as classwork.
Hope this helps and isn't too off the wall. I mention it because it has Spanish language in it, but overall it is English...but the protagonist gets away with having a heavy accent in their English speaking parts. Powerful/political/funny...classic McNally. Maybe worth a look.
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We did some classwork a few years ago using an English and a Spanish text of Sandra Cisneros' The House on Mango Street. The kids adapted scenes and monologues from the texts, swinging back and forth between the two languages. We presented parts of it in an Upper Level Spanish class, but never did a formal performance. The characters are mostly female, which worked for that particular class, but I think that any young adult novel or collection of poems that you can get in both languages could serve as a springboard for exploration. In grad school we had to do scenes in Spanish from Bernarda Alba and Blood Wedding, but that may not be where your kids are at. At any rate, good luck with your class!
Aileen, would you ever mind sharing the translation that you created? I'd love to give it a read to consider producing here in MA. Let me know!
In February 2006, American Theatre magazine had the complete script to Luis Alfaro's Electricidad, a retelling of the Electra story set in a California barrio. It mixed Spanish and English words, which seems to help many ESL students get through scenes from it. It is also great for the native English speakers to be a little confused at all the Spanish words when it is performed in class.
I can't find any sign of the play being published outside of American Theatre, but you can order a back issue of the magazine from TCG for $5.95.
Thanks for all the good suggestions! Now that school is out, I'm looking forward to reading all these recommendations. I appreciate the help!