Standard English and correct grammar are the basis of all professional communication. In addition, each discipline has its own terminology, and each assignment requires you to adapt your style of language to the task.
Why is it important?
Correct grammar and appropriate language enable professionals to communicate effectively and accurately. Misuse of technical language or inappropriate style and language will cause confusion for your reader.
How do I do it?
Test your English grammar and take steps to improve your accuracy if necessary. Read widely to become familiar with the language and style which is normal in your discipline. If necessary, build a glossary of technical language and concepts which are new to you. Look closely at example work, identifying the type of language which is appropriate for your task.