NCTB-SchoolText: A Curriculum-Aligned Bangla/English Text Corpus for Classes 1–10

NCTB-SchoolText is a passage-level text corpus extracted from the official general-curriculum textbooks published by the National Curriculum and Textbook Board (NCTB) of Bangladesh, covering Classes 1 through 10. The dataset contains 58,872 passage chunks drawn from 1,535 chapters across 34 distinct subjects and nine grade levels (Classes 1–8 individually, and Classes 9–10 combined as the SSC book set), stored in a uniform JSON Lines (JSONL) schema. Each record reports the grade, subject, chapter number, chapter title, a deterministic chunk identifier, and the cleaned passage text, allowing any chunk to betraced back to its exact position in the curriculum. The source materials are scanned, image-based NCTB textbook PDFs. Because direct text extraction from these files is unreliable, the corpus was builtusing optical character recognition (Tesseract, via pytesseract) with Bengali, English, or Arabic language models as appropriate, followed by chapter mapping from per-book configuration files and language-aware cleaning to remove scanning artefacts (headers, footers, page numbers) while preserving punctuation, Bangla numerals, and question/list structure. Text isthen segmented into short, pedagogically coherent chunks (median length 351characters) that keep activities, questions, and expository passages intact rather than splitting them mid-unit. The corpus is bilingual (Bangla and English) and additionally contains Arabic-script content in the Arabic and Islamic-studies books, with Sanskrit and Pali rendered in Bengali script. It is intended as a machine-readable, curriculum-aligned foundation for educational NLP applications such as retrieval-augmented tutoring systems, curriculum-grounded question answering, comprehension-set generation, and low-resource (Bangla) language modelling research. Only processed text chunks and chapter-mapping configuration files are released; raw NCTB PDF scans are not redistributed for copyright reasons.