It is quite common for me to receive emails from the editors of a journal asking me, before or after the referees have given their approval, to review and improve my English. Then, the editor suggests a professional English editing service for this purpose.
My question is: Is this common practice, independently on the quality of the English of the manuscript (as an attempt to sell a service), or is it only for the cases where the English really needs improvement?
Here is an example of such an email where the reviewers had no further comments and recommend acceptance, but the editor asks for an English review:
The reviewers judge the technical content of your revised manuscript satisfactory. The English, however, is awkward, and needs improvement. Reviewer comments are included below and/or are attached.
The language quality must be improved. We advise that you seek assistance from a colleague or have a professional editing service correct the language in your manuscript, which can then be resubmitted to us.
AIP and the JAP recommend Edanz for authors who wish to have the language in their manuscript edited by a native-English speaking language editor who is also a scientific expert. Edanz is a global editing service with offices in Japan and China. Use of an editing service is neither a requirement nor a guarantee of acceptance for publication. Please contact Edanz (http://www.edanzediting.com/aip) directly to make arrangements for editing and to receive a quotation regarding price and time.
Please edit the ENTIRE paper.
Please indicate how the manuscript has been revised. Either include a list of changes that addresses each point indicating how the manuscript has been revised as a separate document titled, Response Letter or submit a copy of the manuscript with the exact locations of the revisions titled, Marked Manuscript. That will enable the editors to see whether you have complied with the reviewer comments.