English language learner means a student who: 1. Is at least five years of age but has not reached the age of twenty-one before August first of the year of enrollment; 2. Is enrolled in a school district in this state; 3. Has a primary language other than English or comes from an environment in which a language other than English significantly impacts the individual's level of English language proficiency; and 4. Has difficulty speaking, reading, writing, and understanding English, as evidenced by a language proficiency test approved by the superintendent of public instruction and aligned to the state English language proficiency standards and the state language proficiency test.