California Code, Streets and Highways Code - SHC § 2856

At the hearing protests may be made orally or in writing by any person who would be entitled to protest or object to the ordering of the things proposed to be done at a hearing on the resolution of intention. However, all written protests shall be filed with the clerk of the legislative body at or before the time fixed for the hearing, and any protest relating to the regularity or sufficiency of the proceedings shall be in writing and shall clearly set forth the irregularity or defect to which objection is made.