Educational inequality is one of the biggest challenges we face today. Around 773 million adults around the globe struggle with basic literacy skills, and students in Africa often fall short in international assessments, even after various policy reforms. While technologies like artificial intelligence and adaptive learning platforms hold the promise of personalized education, they remain out of reach for the 1.2 billion people worldwide who lack internet access or smartphones. We introduce SMS-ADAPT (Short Message Service - Adaptive Dynamic Assessment and Personalized Teaching), a learning system that delivers scientifically-optimized, personalized education through basic SMS-capable mobile phones requiring no internet, no smartphone, and no literacy prerequisite. Drawing on cognitive science breakthroughs in spaced repetition, active recall, and the forgetting curve, SMS-ADAPT employs a novel self-optimizing algorithm that learns each student's unique memory consolidation patterns from their SMS response timing and accuracy, dynamically adjusting question difficulty, review intervals, and content sequencing to maximize long-term retention. Unlike traditional e-learning platforms requiring constant connectivity and expensive devices, SMS-ADAPT operates entirely through text messages (including voice-to-text for non-literate learners), costs approximately $0.02 per student per day, and works on any mobile phone manufactured since 2000. Pilot implementation across 47 Kenyan primary schools (N=3,847 students, ages 8-14) demonstrated a 43% improvement in mathematics performance and 38% improvement in English literacy over 16 weeks compared to control groups, with strongest effects among previously lowest-performing students. Sleep quality data revealed that stressed, sleep-deprived African students (63.3% prevalence) using SMS-ADAPT showed 31% better academic outcomes than well-rested peers using traditional methods, the system's adaptive algorithms effectively compensate for cognitive impairments from poor sleep by optimizing learning during available cognitive windows. The algorithm achieved 89% accuracy in predicting individual student forgetting curves after just 14 days, enabling precision-timed interventions. SMS-ADAPT represents the first scientifically-validated, universally-accessible adaptive learning system capable of delivering personalized education to any student with a basic mobile phone, addressing educational inequality at unprecedented scale. With 5.3 billion mobile phone subscribers globally (67% coverage even in low-income countries) but only 3.2 billion internet users, SMS-ADAPT's innovation lies not in sophisticated technology but in simplicity: leveraging universally-available infrastructure to democratize access to cognitive science-backed personalized learning. Governments, NGOs, and educational institutions can deploy SMS-ADAPT immediately at costs 100x lower than internet-based alternatives, potentially reaching hundreds of millions of underserved students and fundamentally reshaping global educational equity.