If you write English as a second language, the errors that hurt you are not exotic. They are the same ten, repeated, in every message. Fix them once and the improvement is permanent, because these are patterns rather than vocabulary.
None of this is about accent, and none of it is about sounding native. It is about not making a reader stop.
1. Agree is a verb
I am agree with your plan.
I agree with your plan.
In English, agree is something you do, not something you are. The same goes for disagree. You never need to be before it.
2. Some nouns have no plural
Information, advice, feedback, equipment, research, software, news and homework are uncountable. They never take an s and never take a.
Thank you for the informations and your advices.
Thank you for the information and your advice.
When you need to count them, add a unit: two pieces of feedback, three items of equipment.
3. Deadlines take by, not until
This one causes real confusion, because until and by mean different things.
I will send the report until Friday.
I will send the report by Friday.
By means at or before that point. Until means continuously up to it, so the first version says you will be sending all week.
4. Small words carry meaning
Articles look decorative and are not. A means one of many, the means the specific one we both know about.
I am in meeting, I will send you document after.
I am in a meeting. I will send you the document afterwards.
A meeting means one of your meetings. The document means the one already under discussion. Dropping both makes the reader guess.
5. Revert does not mean reply
Revert means to go back to a previous state. In many offices it is used to mean reply, and outside those offices it reads as an error.
Kindly revert back to me at the earliest.
Could you reply by Thursday?
Back is also redundant after revert, and "at the earliest" is not a deadline. Give a date.
6. Name the action instead of requesting action
"Please do the needful" tells the reader that something is required and not what.
Please do the needful regarding the invoice.
Could you approve invoice 2214 so finance can release the payment?
Every request should survive this test: could a stranger read it and know exactly what to do?
7. Kindly, once, or not at all
Kindly is not wrong. It is just heavy, and it multiplies. Two kindlies in one message read as pressure rather than politeness.
Kindly find attached. Kindly review and kindly confirm.
The draft is attached. Could you review it and confirm by Wednesday?
Please works everywhere kindly does, and it does not stack.
8. A finished time takes the past simple
If the sentence names a finished time, use the simple past. Have plus a past participle is for things connected to now.
I have sent it yesterday.
I sent it yesterday.
Yesterday is closed. Use "I have sent it" only when you are not saying when.
9. Questions do not need help twice
Once you use can, could, do or will at the front, the main verb stays in its base form.
Can you to send me the file? Do you can join at 3?
Could you send me the file? Can you join at 3?
The same rule catches "I will can" and "Did you went".
10. For a length of time, since a starting point
I work in this team since three years.
I have worked in this team for three years.
For takes a duration. Since takes a date or event: since March, since I joined.
A bonus that matters more than grammar
Dear Sir, I would like to humbly request if you could kindly consider to help me with a small doubt regarding the below mentioned matter.
Hello, I have a question about the pricing model on page 4. Could I ask you two things about it?
Long politeness is not respect in English. It reads as nervousness, and it buries the request. One greeting, one clear ask, one thank you at the end. That is the whole formula.
Keep this list nearby
- No "am" before agree or disagree.
- No s on information, advice, feedback, equipment, research or software.
- Deadlines use by, never until.
- Every noun has a or the in front of it unless it is uncountable or plural.
- Reply, not revert. Name the action, never "the needful".
- Kindly appears at most once, or is replaced by please.
- Finished time takes the simple past.
- After can, could, do or will, the next verb is in its base form.
- For a duration, since a start point.
- One greeting, one ask, one thank you.
Read your message once against this list before sending. Nine times out of ten you will change one thing, and that one thing is the one that would have made the reader pause.