Firen was the primary language in what has become the eastern states of the Union of Six. It may be considered "Proto-Fulren", the primary language of the Empire.
Firen is am agglutinative and highly-inflected language with mostly ergative-absolutive alignment, however particularly active verbs mark their subject in the ergative case (this is called "Split-S" alignment) and fairly free word order, but the most basic word order is VSO. It has 17 Firen:cases, 6 Firen:moods, 5 Firen:voices, and 3 Firen:noun classes based on an animacy hierarchy.
The native orthography of Firen is baofusk, or 'blocked-writing'.
Main article: baofusk
Transliteration of baofusk into the latin alphabet is mostly straightforward. Most letters refer to their IPA values, with the exceptions of ⟨f⟩ /ɸ/, ⟨v⟩ /β/, ⟨č⟩ /tʃ/, ⟨j⟩ /dʒ/, ⟨r⟩ /ʀ/, ⟨ů⟩ /ɵ/, ⟨ao⟩ /aʊ/ and all the rhotic vowels, which are written as digraphs with ⟨ṙ⟩. Syllable divisions, though marked in baofusk, are not preserved when transliterating.