Common Tongue: The language used throughout Westeros consisting of minor variations and regional accents but understandable in all Westerosi regions.
Old Tongue: The language of the First Men. This language is only remembered by giants and some free folk from beyond the wall. The language must have been learned by one such person to be understood in character and is allowed by admin approval only.
High Valyrian: The language of the old Valyrian Freehold. Someone fluent in High Valyrian can understand and communicate in low Valyrian well enough. Fluency in High Valyrian is limited to the Valyrian houses and Maesters with their languages chain. Some nobles may have received some instruction in the language as part of a refined education but they would have limited conversation ability prioritizing the reading of inscriptions or old texts or a general knowledge of formal phrases.
Low Valyrian: Bastardizations of High Valyrian used in various regions of Essos.
Ghiscari: a largely extinct tongue. It was spoken five thousand years ago by the Ghiscari people of the Old Empire of Ghis, which was destroyed by the Valyrian Freehold. Ghiscari was supplanted by a "mongrel" blend with High Valyrian, though it is still spoken by some, and engraved Ghiscari glyphs can be found on various old objects. The following languages are bastardizations of Ghiscari and High Valyrian.
Dothraki: The language of the Dothraki. Only specific persons who have had reason to interact with the Dothraki for an extended period of time would know the Dothraki language such has Maesters with the languages chain.
The Summer Tongue: The language used by people from the Summer Isles