because people speak English
Don't worry about English that much.you are not the one and only person who worry about their English.And also you know English.I can't say it is too bad.only thing is you can improve your English.If you like you can join to the conversation group and add new conversation every day.then others will help you to find out your mistakes.
Improving English takes time! And, we have to practice four skills including listening, speaking, reading and writing! Practice makes perfect! So, only practice! I wish you all the best!