All in One SEO is one of the most translated plugins of all time. It's been translated into more than 54 languages. You can find the translation status of any language on WordPress.org here.
Once a language reaches 90% translated, the language pack can be installed on your WordPress site. You can do this by going to Dashboard » Updates » Translations and you'll see an Update Translations button if there are available language packs for your site's language.
Please note that the release of plugin language packs is controlled by WordPress.org and not the plugin developers.
If you're interested in contributing translations, you can do so on WordPress.org here.
Further reading: Translating All in One SEO.