Mastering a second language is a huge achievement, but English is filled with subtle rules and exceptions that can challenge even the most dedicated learners. For ESL (English as a Second Language) students, reaching professional fluency often becomes difficult due to recurring grammar habits that are hard to break.

Whether you’re writing an academic essay, a business email, or a blog post, small mistakes can distract readers from your ideas. This guide explores the 10 most common grammar mistakes ESL students make and shows how to fix them permanently using modern tools like an AI grammar checker, AI writing assistant, and platforms like CorrectifyAI.