California Code, Education Code - EDC § 44856

(a) The governing board of a school district, for the purposes of providing bilingual instruction, world language instruction, or cultural enrichment, in the schools of the school district, subject to the rules and regulations of the state board, may conclude arrangements with the proper authorities of a foreign country, or of a state, territory, or possession of the United States, for the hiring of bilingual teachers employed in public or private schools of a foreign country, state, territory, or possession.  To be eligible for employment, the teacher must speak English fluently.  Any persons employed pursuant to this section shall be known as a “sojourn certificated employee.”

(b) A person shall not be hired as a sojourn certificated employee by a school district unless he or she holds the necessary valid credential or credentials issued by the commission authorizing the person to serve in a position requiring certification qualifications in the school district proposing to employ him or her.  The person may be employed for a period not to exceed two years, except that thereafter the period of employment may be extended from year to year for a total period of not more than five years upon verification by the employing school district that termination of the employment would adversely affect an existing bilingual or world language program or program of cultural enrichment, and that attempts to secure the employment of a certificated California teacher qualified to fill the position have been unsuccessful.  The commission shall establish minimum standards for the credentials for sojourn certificated employees.