Language Development Research: An Open-Science Journal (ISSN 2771-7976) was established in 2021 to meet the field’s need for a peer-reviewed journal that is committed to fully open science: LDR charges no fees for readers or authors, and mandates full sharing of materials, data and analysis code. The intended audience is all researchers and professionals with an interest in language development and related fields: first language acquisition; typical and atypical language development; the development of spoken, signed or written languages; second language learning; bi- and multilingualism; artificial language learning; adult psycholinguistics; computational modeling; communication in nonhuman animals etc. The journal is managed by its editorial board, and is not owned or published by any public or private company, registered charity or nonprofit organization. We invite submissions that meet our criteria for rigour, without regard to the perceived novelty or importance of the findings. We publish general and special-topic articles (“Special Collections”) in a rolling format, to ensure rapid, cost-free publication for authors.