Many publishers recommend editing and other language services, either in house or outside the publishing company. The Springer Nature company currently recommends "English language editing" to reach "Nature Research" standards, and "scientific editing" that examines all aspects of a text.
The prices (in USD) are very different:
For English-language editing, the price is "based on wordcount and starts as low as $87".
For scientific editing, the price is "per paper and word count", and starts at only $1500"
The latter pricing is presumably the base rate for a short or standard-length paper, with longer papers being charged more based on the word count above a threshold).
So... the most economical approach here would be to have your scientific content checked by colleagues in a mutual exchange of volunteer help, and then have the language improved by further editing.
Comments on this post are welcome! (Research Co-op, Admin)
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Peter J. Matthews, Chief Admin.,
The Research Cooperative,
Auckland & Kyoto.
Contact: researchcooperative [at] gmail [dot] com