Two or more school districts may, upon the nomination or joint nomination of the county superintendent, district superintendent or supervising principal under whose supervision such districts may be, join in the employment of a supervisor or teacher of drawing, music, or other special subject, for part or all of the schools of such districts and may jointly prescribe his duties and fix and pay his compensation, under and subject to the provisions of this article governing the employment and tenure of professional employes. Such employment of teachers of special subjects shall include, for the purpose of easing the transition period of immigrants residing in such school districts, the employment of special teachers who speak the idiomatic or colloquial language of immigrants residing in such school districts.