Q: Is it self-plagiarism if I publish a translated version of my previously published paper?

Generally speaking, journals are not in favor of publishing content that has already been published, even if it has been published in another language. In fact, most journals require you to declare if your manuscript has been published previously.

However, publishing a translated version of an already published article is possible under certain circumstances. This is referred to as secondary publication and is not unethical as long as you are completely transparent about it. The ICMJE guidelines have a section on Acceptable Secondary Publication. Please go through these guidelines and ensure that you follow the norms that should be maintained for such publications to be ethical and acceptable. 

Most importantly, you should first obtain written permission from the journal that published your original paper. Once this journal authorizes, you will need to provide the permission letter to the target journal where you intend to publish the translated version. When submitting to this journal, please explain in your cover letter that this is a translation of a previous publication. Additionally, the title and introduction should also explain to readers that this is a secondary publication and cite the original.

Note that as per ICMJE, secondary publications may be deemed justifiable if they are intended to reach a wider audience. Therefore, you should mention in your cover letter why you feel your research findings should be disseminated globally and how it will benefit a global audience. If your argument is convincing enough, the journal might agree to publish the paper.

Related reading:

• Is it ethical to translate a published article into another language and publish it?
• Can I republish my Japanese article in English?
• Can I publish two papers in different languages using the same data and methods, but as a more elaborate version?