This article describes the use of African American English (AAE) in the written and oral language of African American adolescents who struggle with writing. Written and oral language samples of 22 African American 10th-grade students were transcribed, analyzed, and coded for AAE, grammatical errors, spelling errors, and punctuation errors. Four patterns were identified in the students' written language samples that were also produced in their oral language samples and were consistent with AAE dialect use--copula variability, subject-verb agreement, cluster reduction, and differences in vowel pronunciations. Even at the secondary grade level, dialectal differences play a role in the types of errors that speakers of AAE produce during tasks that require standard written English. Professional development of general education classroom teachers who teach writing to AAE-speaking students could encourage the use of contrastive analysis procedures and dialect awareness tasks to help AAE speakers become more proficient with standard written English.