If you want to contribute to SEOPress, you can help us by providing your own translation.
There are few steps to do this.
1/ Check on translate.wordpress.org if the translation doesn’t already exist.
2/ Read the official Translation Handbook about GlotPress and how translation works with WordPress.
3/ Translate the plugin using GlotPress or another tool like Poedit (free). Please do not put links or any other ads into the translation.
4/ Send us your PO/MO files to firstname.lastname@example.org. If you use GlotPress, just ping us by email to trigger the approval process.
5/ Done! Your name (or Twitter account) will be added in the readme.txt of the plugin and here if you want.