Fallon (2001, 2004) notes intervocalic lenition, such as /b/ → [β]; syncope, as in the name of the language, /bɨlín/ → [blín]; debuccalization with secondary articulation preserved, as in /dérekʷʼa/ → [dɛ́rɛʔʷa] 'mud for bricks'.

Intriguingly, the ejectives have voiced allophones, which according to Fallon (2004) "provides an important empirical precedent" for one of the more criticized aspects of the glottalic theory of Indo-European.

Although the Geʽez script is usually used for Semitic languages, the phonemes of Bilen are very similar (7 vowels, labiovelar and ejective consonants).

The script therefore requires only a slight modification (the addition of consonants for ŋ and ŋʷ) to make it suitable for Bilen.

In 1985 the Eritrean People's Liberation Front decided to use the Latin script for Bilen and all other non-Semitic languages in Eritrea.