For buyers contracting authority
Choose 48319000 when the proofreading or correction capability is the product, not a feature of something larger. A standalone spelling and grammar engine, a writing-assistance platform, or a language-specific correction tool for learners belongs here.
The boundary that trips contracting authorities is word-processing (48317000). A word processor ships with spell-check baked in, so if the deliverable is the editor itself, that is 48317000; reserve 48319000 for cases where the checking engine is what gets specified and paid for. One step up, the parent 48310000 fits when the brief spans document creation broadly and no single sub-category dominates.
Language technology blurs the lines here. Modern correction tools lean on natural-language processing, so a contract framed mainly as an AI or text-analytics build can point toward an AI services code instead. Set the primary CPV code by the dominant purpose: if the point is catching and fixing errors in text, keep it here; if the point is a broader language-processing platform, the AI route fits better.