Can I contribute to the translation of the plugin?
The short answer; yes, you can.
The longer version:
Yoast SEO free
You can help translate our free Yoast SEO plugin by going to WordPress.org. There you can see how many strings are already translated in your language. You can click your language to start contributing. You can also use the WordPress.org translation handbook as a guideline.
After 10 years of translating on translate.yoast.com, we’ve decided to move the translations for all our Premium plugins to TranslationsPress. This service allows us to use language packs for our premium plugins, and it helps you translate faster because it offers Translation Memory. Of course, we hope you’ll keep translating our Yoast plugins.
To sign up for an account, please go to translationspress.com/app/yoast. Once you’ve created your account, you’ll automatically be added to Team Yoast where you can translate all our premium plugins. Once you’re logged in, you’ll be able to add your translations. Once they’re approved, we will include them in an upcoming version of the plugin.