Even as the usual persons cry "it never happened!", BuzzFeed comes in with two persons who back up Dolores Huerta's story:
http://www.buzzfeed.com/evanmcsan/sources-bernie-supporters-did-chant-english-only-at-latina-l?utm_term=.akOpJ4jpB#.ar1rNoerR
CNN has picked up the story as well - and the Sanders campaign, notably isn't denying it:
http://www.cnn.com/2016/02/20/politics/dolores-huerta-english-only-sanders-organizers/index.html?sr=twpol022116dolores-huerta-english-only-sanders-organizers1250AMVODtopLink&linkId=21446314
Even ThinkProgress, which is usually so very friendly to Bernie, ran with the story and didn't attack Huerta:
http://thinkprogress.org/politics/2016/02/20/3751830/dolores-huerta-interview/