Languages in Babylon 5

There are three primary languages used on the Babylon 5 station: English, as well as the fictional Centauri and Interlac. English is mentioned explicitly as the "human language of commerce," and is the baseline language of the station (written signs appearing in all three languages). Other human and alien languages do exist in the Babylon 5 universe, though with the exception of Minbari, hearing them spoken is uncommon; when aliens of the same species are speaking to one another, the words heard are English, though it is presumed they are speaking their native tongue. Only when in the presence of humans can the alien language be heard, to stress that the humans cannot understand what is being said. With the exception of the Minbari tongue, few other alien languages are actually heard aloud on a regular basis.

The Gaim, pak'ma'ra, and Vorlons do not speak directly in English; in the case of the pak'ma'ra, either because they refuse to learn any language other than their own, or because they are incapable of making human sounds. Members of these races instead make use of real-time translation devices.

The principal human characters speak with an American English accent, with the exception of Marcus Cole, who speaks with Jason Carter's natural British English accent. Susan Ivanova, born in Russia, speaks with an American accent, as her character was raised and schooled outside Russia. Her father speaks with a distinct Russian accent, as does her brother. Various other minor human characters speak English with recognizable regional accents. Ambassadors Delenn and Londo Mollari, both alien characters, speak with distinct accents similar to Slavic. Delenn speaks with actress Mira Furlan's normal Croatian accent; most other Minbari have native-speaker accents for English (e.g. American English for Lennier, British English for Neroon). Londo's accent was developed independently by actor Peter Jurasik and was imitated by William Forward, who played Lord Refa. Straczynski has described Londo's accent as being that of the "old school" of the Centauri Imperial Court. Narns tend to speak in native-speaker (generally British) accents as well; Andreas Katsulas adopted a dramatic British accent to portray G'Kar.