The audio language is and probably will never be very well supported. Most websites and APIs do not provide any language information whatsoever. Hence, it is difficulty to filter streams according to their audio or subtitle language. Some website do contain metadata about the audio language. The labels of these streams will have an indication about the available languages. The label can be customized under: Gaia → Settings → Interface
Providers under the Universal category search sites that contain content from all across the world, which is the case with most torrent sites. Some of them support language detection, like Zooqle. Providers that are not listed under the Universal category contain content in a specific language. Many of these language-specific providers are available in Gaia, like German, French, Russian, Polish, and Korean. However, the majority of streams by far are only available in English. Providers that are listed under a specific language can still return streams in a different language, often English. All foreign language providers are not well maintained. Feel free to update them yourself and submit the code to Gaia for integration into the addon. If you want to request a specific provider in your language, please follow the provider suggestion instructions given in another help topic.
Last Updated: 06 Jan 2018