(There are other counties listed but I decided focus on the Lompoc Valley)
Below are  a few key-points pertaining to DLLs. 

At least one in five students in San Diego County schools speaks a language other than English.

These are the 10 top languages spoken in San Diego and the number of speakers of each language:

Spanish (89.972), Arabic (3.077), Filipino (2.901), Vietnamese (2.495), Mandarin (1.039), Korean (797), Russian (506), Cantonese (298), Hmong (90), Punjabi (36).

The percentage of San Diego Unified English Learners students who were deemed fluent, or English proficient, was 17 percent in the 2016-2017 school year, up from 11 percent two years before, according with to district data. (sandiegouniontribune.com)

After reading all these information we can see how every year the number of Dual Language Learners are increasing.

I couldn't find much from California Department of Education web site. It looks like it has a lot of information but more related to California statistics in general, or at least I couldn't find easily by searching in that website.

I have found more information about Dual Language learners in websites like Cde.ca.go, voiceofsandiego.org, Sandiegounified.org and ed-data.org.

there is an interesting article about how San Diego County needs to improve their English-Learner Program.

I work for San Jacinto Unified. My site is Hyatt Elementary. There is a total of 416 students. 9.6%  of the population is African American, 1.4% is American Indian or Alaska Native, 0.2% are Asian, 79.1% are Hispanic or Latino  and 7.9% is White.

San Jacinto Unified Report (33-67249)
Report Description

NameTotalAfrican AmericanAmerican Indian or Alaska NativeAsianFilipinoHispanic or LatinoPacific IslanderWhiteTwo or More RacesNot ReportedClayton A. Record, Jr., Elementary | 554 | 5.4% | 0.9% | 0.4% | 1.3% | 75.3% | 0.0% | 14.1% | 2.7% | 0.0%
De Anza Elementary | 688 | 6.7% | 2.3% | 0.6% | 1.2% | 69.6% | 0.3% | 16.3% | 3.1% | 0.0%
Estudillo Elementary | 675 | 7.4% | 8.0% | 0.3% | 0.1% | 69.8% | 0.3% | 10.2% | 3.9% | 0.0%
Hyatt Elementary | 416 | 9.6% | 1.4% | 0.2% | 0.0% | 79.1% | 0.0% | 7.9% | 1.7% | 0.0%
Megan Cope Elementary | 1,010 | 8.6% | 2.0% | 1.6% | 1.5% | 72.8% | 0.3% | 10.8% | 2.5% | 0.0%
Monte Vista Middle | 916 | 8.1% | 1.1% | 1.0% | 0.9% | 73.0% | 0.7% | 11.9% | 3.4% | 0.0%
Mountain Heights Academy | 144 | 7.6% | 2.8% | 0.7% | 0.0% | 63.2% | 0.7% | 17.4% | 7.6% | 0.0%
Mountain View High | 250 | 12.0% | 2.4% | 0.0% | 0.0% | 73.2% | 0.4% | 8.8% | 3.2% | 0.0%
Nonpublic, Nonsectarian Schools | 27 | 18.5% | 0.0% | 0.0% | 0.0% | 51.9% | 3.7% | 22.2% | 3.7% | 0.0%
North Mountain Middle | 1,056 | 8.4% | 2.6% | 0.5% | 0.3% | 74.2% | 0.5% | 11.3% | 2.3% | 0.0%
Park Hill Elementary | 846 | 10.9% | 2.0% | 0.7% | 0.7% | 68.1% | 1.3% | 12.8% | 3.5% | 0.0%
San Jacinto Elementary | 525 | 9.9% | 1.7% | 0.0% | 0.0% | 78.9% | 1.0% | 6.3% | 2.3% | 0.0%
San Jacinto High | 2,676 | 7.8% | 1.9% | 1.1% | 1.4% | 73.4% | 0.7% | 10.8% | 2.9% | 0.0%
San Jacinto Leadership Academy - Magnet | 349 | 6.0% | 1.4% | 1.7% | 2.6% | 68.2% | 0.6% | 16.0% | 3.4% | 0.0%
San Jacinto Valley Academy | 1,436 | 4.5% | 1.3% | 1.9% | 0.8% | 67.1% | 0.6% | 22.1% | 0.9% | 0.7%

Report Totals

NameTotalAfrican AmericanAmerican Indian or Alaska NativeAsianFilipinoHispanic or LatinoPacific IslanderWhiteTwo or More RacesNot ReportedSan Jacinto Unified | 11,568 | 7.8% | 2.1% | 0.9% | 0.9% | 72.0% | 0.6% | 12.8% | 2.7% | 0.1%
Riverside County | 428,494 | 6.0% | 0.5% | 3.1% | 1.9% | 64.2% | 0.3% | 20.2% | 3.2% | 0.5%
Statewide | 6,186,278 | 5.4% | 0.5% | 9.3% | 2.4% | 54.6% | 0.5% | 22.9% | 3.6% | 0.9%

Data Reporting Office
California Department of Education
1430 N Street
Sacramento, CA 95814

DRO@CDE.CA.Gov  |  Web Policy

Los Angeles

CDS Code 19-00000-0000000

                                                                  Armenian                                 Cantonese                                 Korean                                 Mandarin (Putonghua)                                 Spanish                                 All Other                                              View by Language#%

View Table Data 

Languages of English Learners2014-152015-162016-172017-182018-19All Other  | 23,402  | 23,753  | 23,033  | 21,797  | 
Armenian  | 6,150  | 6,711  | 6,194  | 6,192  | 
Cantonese  | 5,172  | 4,645  | 4,296  | 4,187  | 
Korean  | 4,442  | 4,426  | 3,781  | 3,510  | 
Mandarin (Putonghua)  | 7,110  | 7,648  | 7,671  | 7,936  | 
Spanish  | 303,602  | 299,286  | 284,317  | 261,688  | Total | 349,878 | 346,469 | 329,292 | 305,310 | N/A

Rick Mayfield, former principal of Pacheco Elementary and current director of learning and achievement for San Luis Coastal, said Pacheco had 80 applicants for 16 spots last March during open enrollment.

"We have 160 students from the coast who currently attend Pacheco and another 50 on the current waiting list to attend," Mayfield said. "There's a lot of kids coming into town every day from the coast, riding the bus, who want to participate in this particular program."

San Luis Coastal is currently proposing to fill the gap by phasing in a dual-immersion program at Baywood Elementary School. The program would start with the kindergarten class in the fall of 2020-21 and continue to add a grade level each year.
This is an article from the new times.
I couldn’t find any data that shows the number/percentage of young dual language learners in San Luis Obispo County

In my school site, the number of DL's, students that speak Spanish in Kindergarten is a total of 88, and 98.87% if we look at grades from kinder to 12th grade. Following with only 2, another non-English language. It was interesting to find out that our school site has two students that are non-English language. 

Within my school district, there is one bilingual site, and that is Venetia Valley School, this school site is setting the stage for other sites to explore the idea of becoming bilingual programs. 

Although we have another school in our district or programs that call themselves bilingual, the question remains, what truly takes to be a bilingual program?

Although, while the idea of becoming a bilingual site has been proposed in the past years. But it has been not very easy to hire and retain teachers, especially at our site. In our school site, there are only two teachers fully bilingual, me being one of them. The rest of the staff are monolingual English, been the predominant language of teachers.

https://www.cde.ca.gov/ds/sd/cb/cefelfacts.asp

I Unfortunately, had a difficult time finding information on Dual Language Learner in the county of Sacramento. However, what I was able to find a Dual Language Immersion Program in our area. The first one I found is a DLL program for transitional kindergarten, Kindergarten and first grade, provided by the St. Philomene School located in the Sacramento county. According to the information found on their website, the students in the program spend half a day learning English and the other half learning Spanish. http://stphilomene.org/dual-immersion-program

Lastly, on DLL’s, I also found that the Sacramento County Unified School District, along with many more are now providing dual immersion programs aiding our DLL community with English alongside their “target” language (SCUSD). https://www.scusd.edu/district-program/language-immersion-and-other-alternative-programs
Languages  of English learners:

Languages of English Learners 2014-15 2015-16 2016-17 2017-18 2018-19
All Other | 53 | 53 | 45 | 45 |
Filipino (Pilipino or Tagalog) | 14 | 12 | 14 | 17 | 
Ilocano | 6 |  |  |  | 
Khmer (Cambodian) | 5 | 3 |  |  | 
Korean |  |  |  | 3 | 
Mixteco |  | 5 | 4 | 4 | 
Punjabi | 9 | 12 | 11 | 6 | 
Spanish | 3,168 | 3,165 | 2,983 | 2,803 | 
Vietnamese |  |  | 4 |  | Total | 3,255 | 3,250 | 3,061 | 2,878

To accomplish this goal they have the dual language immersion program. They need to have a setting to provide academic instruction for the native speakers. The goal is high academic achievement and first and second language proficient and cross the culture of understanding. The transition or Development Program it need to provide pupils native language for literacy and academic instruction and enable an English learner to achieve and meet the state adopted academic. Structured English Immersion that classroom instruction to provide English with the curriculum and presentation to be design programs of structured for the English Immersion. 

cde.ca.gov

It also became apparent how much the focus was on school age children versus those under the age of 5. We already have the research to support how much language and brain development occurs in these early years, so why are there no stats for these children who are in the process of early language development. It’s better to be proactive than reactive.

www.ed-data.org