Interesting. 27.455 MHz LSB, 27.695 MHz LSB and 27.705 MHz LSB are often heard when 11 meters is open (I usually hear activity on 27695 LSB and 27455 USB before the others). I've only logged 27.955 MHz USB a couple times in years past if my memory serves me right, I haven't heard too much on it lately (at least not compared to the other three frequencies).
It would be awesome if you could provide other Southern California / Los Angeles 11 meter Spanish language frequencies. I also wonder about the following:
26.225 USB - Seems to be popular with stations in Mexico, but I've also heard Caribbean sounding traffic here.
26.555 LSB - Often just as busy as 27.455 USB, I've always considered it the "low channel" counterpart to 27455 USB
26.585 AM - I know this one is active with Mexican accented Spanish traffic - and often stations will start on 26585 AM and move up or down to avoid QRM. QSY frequencies include 26.575 AM, 26.595 AM, 26.605 AM and 26.615 AM. The same thing applies for 26225 USB (when 26.225 MHz is busy, I'll check 26230 USB, 26235 USB, 26240 USB and 26245 USB) and 26.555 LSB. The pattern here is that SSB operators seem to use 5 kHz steps and the AM operators just use the regular old 10 kHz channelized steps found in exports.
Videos I've found online of operators using 26.225 USB feature stations with modified 100 watt 160m-10m HF ham gear and high power Galaxy export radios, specifically the Galaxy DX 98VHP (the "VHP" standing for "Very High Power" - apparently rated at 200w PEP on SSB and 250w or so peak AM power) and directional antennas of various types. The stations seemed to be located in Mexico or Southern California. Of course, they could be working DX with stations in Dominican Republic, Puerto Rico, and various other parts of Latin America, as is the case with dozens of other frequencies on 11 meters.
I remember finding a frequency list on a Mexico-based 11 meter freeband DX radio club and they listed 26225 USB, 26555 LSB, 26705 AM, 26715 AM, 27065 AM, 27455 USB and 27555 USB as "official" calling frequencies.