If English is not your primary language, you want to be confident that your already translated technical documents are of the highest quality, with no terminology, sentence structure, word usage, or spelling errors that would detract from the value of the information. Most of these errors will get past standard spell-checker software, and are only visible by a human eye review. A technical proofread will avoid the embarrassment of publishing an error-filled, translated document, and help maintain the integrity of the data, conclusions and authors.