Q: Is submitting two similar papers in different languages duplicate submission or publication?

If detected before publication, this will be considered a case of duplicate submission. However, if the two papers are published, the matter will get worse and it will be a case of duplicate publication. If duplicate publication is detected, one or both of your published papers may be retracted. Retraction due to academic misconduct will have a damaging effect on your reputation. In some cases, offenders are banned from publishing in that journal for 3-5 years.

You should not have submitted two similar papers to two different journals at the same time. The ideal way would be to wait till one of the articles is published and then publish a translated version of the same article as a secondary publication, with the permission of the editors of both journals.

You should immediately withdraw your paper from one of the two journals. Once the article in the other journal is published, you can inform the editor that you wish to publish a translation of your published article and take it forward as a secondary publication, making sure to cite the original article in the translated version.