Living Languages
Thousands of languages have arisen throughout the tens of thousands of years since the Arrival. Many worlds have developed numerous widely-spoken languages, some of which survive into the present. At the interstellar level, once the Array became radio-noisy, regional languages developed. Currently the living languages spoken on multiple worlds are in four main families: The Salanic, The Anguan, The Ushanti and Morathi.
Salanic
There are two Salanic languages, Salanic and High Salluminic, one associated language, Warspeak.
Salanic is a simple and practical language well suited to a placid agrarian life, with a huge vocabulary, and a grammar derived from the High Salluminic. Salanic is also very beautiful, and much poetry has been produced in that tongue through the millennia since its introduction.
The High Salluminic is the holy language. It has remained unchanged for thousands of years, and consists of a chant that takes 40 minutes to complete at a standard pace. All of the words are included in the chant, some used many times, and some only once. The holy work can only be fully understood as a whole, with some passages quite difficult to decipher in isolation. It is claimed that knowing about both rudimentary agriculture and basic psionics are enough so that the reader can glean the rest from the mutually interdependent analogies and parables.
Segments of the High Salluminic can be referred to by codes, and the Priesthood uses these to communicate longer passages. This method of coding can be very difficult to decipher, as the key string being used is rotated regularly.
Though the stories from the High Salluminic are adapted into stage productions, the use of the actual words are not to be used except as approved the the Church. As the the language itself, critics say that the holy language of the Church is an artifact with only ceremonial value.
Sallumin also has a secular military language, Warspeak, from before the Compact, and some still speak a form of it. This language did not have Salanic roots, though it is usually grouped with Salanic due to the associated kingdom. A form of Warspeak is still used by Sallumini officers. The Priesthood approves, as they have it from the Word that in matters of war, the rational mind will prevail. Thus, Warspeak is not a Salanic language.
Anguan
The First Dominion, that of Angu, dominated the Deep for a thousand years, and areas that were under its control when the Dominion collapsed kept a strong influence from their time as subject worlds. Of the three major Anguan languages (Almerandi, Osteroszan, and Trienese) each has dual roots, one from the legacy of the First Dominion, and another from a local cultural identity.
The Ushanti language proper is only spoken in the small territory the Union has maintained, near the top of the Array. A bastardized form of Ushanti is spoken on many worlds still in the Void, but mostly underground, by cultists and conspiracy nuts.
Shadarin is spoken by Imperial citizens on the home world of Shadir, and by military and intelligence personnel in the field, but in the Empire, most subjects are not expected to learn it. Some of these speak local languages, but usually Compact Standard, for which lessons are available on radio broadcasts throughout the Array, has become the language for interstellar trade and diplomacy within the Empire.
Dead Languages
The Bystanders had a language that may have small influences on the Sharer culture, but that language group was phased out thousands of years ago in favor of more advanced linguistic ideas.
Gelloinese is an Anguan language that is now only spoken on a few worlds, with diminishing speakers in the midst of more modern languages like Osteroszan and Trienese.
Artificial Languages
Compact Standard was created 1500 years ago for commerce by Almerand and Sallumin, but it has widened into a fully developed language for most uses, though not well-suited to poetry. Since then it has been adopted as an international language in most of the Array (everywhere but Triene, where it was officially discontinued over 200 years ago). It’s used in science and technical fields, even in parts of Triene.
Warspeak has already been covered.
Base 80 is the language of the Artifact Tablets. Each usually has had multiple levels to the meaning from various approaches to translation. Some still have not been adequately interpreted. Some tablets are still found, once a century or so.