I work for a journal which is in this field. Grammatical errors are OK for a manuscript as long as reviewers can understand what you are reasoning. We will copy

I work for a journal which is in this field. Grammatical errors are OK for a manuscript as long as reviewers can understand what you are reasoning. We will copy edit for grammar or style later if accepted. We won't change the significant findings of a manuscript though, so if the paper is unclear and gets rejected by referees, that is how it stands. Referees will usually ask for revision if something is not particularly clear. But if a manuscript came in that was not comprehensible it runs the risk of being summarily rejected.