Tsi exists in a state of relatively differentiated diglossia, although the differences between the scriptual-bureaucratic inscription Tsi and spoken Tsi are not so gapingly distant as to be mutually incomprehensible. Perhaps it is better to think of inscription Tsi as an unusually differentiated, archaising register of Tsi. It is important to note that the 'ideal' of inscription Tsi (which reflects to a greater or lesser extent the cherry-picked spoken Tsi of centuries past) is typically diluted to a greater or lesser extent by influence from spoken Tsi.

Inscription Tsi makes use of some archaic or unusual vocabulary which is no longer in use in speech. It also makes use of a number of archaic constructions, some of which we have seen in the grammar presented so far. Most characteristically, it maintains the use of a differentiated classifier system (collapsed in spoken Tsi). It does not typically make use of the auxiliaries, and retains more of the morphological machinery used to distinguish perfectives and imperfectives (many perfectives have a final -d, which occurs much more rarely in normal spoken Tsi). In its spoken form it lacks many of the contractions found in normal speech and has some elongated versions of morphemes.

A form of spoken inscription Tsi is used in prayers and magical invocations, in formal addresses to government (which in a sense are the same thing), in legal proclamations and so on. It is in this use (the deliberate preservation of archaising and indirect language) that Inscription Tsi began, and it has a much longer tradition as a spoken register than in writing. However, since the Kangshi script was imported into the Tsi-speaking area, inscription Tsi has also been used in writing and of course on imperial inscriptions. These inscriptions are one of the most visible signs of imperial power throughout the archipelago - even if very few of its residents can read them.

Whilst very few people have any kind of active command of inscription Tsi and a whole small industry flourishes around those who do (magicians and folk healers, priests, scribes, official petitioners etc), there are many native speakers of Tsi - certainly more than any other language in the archipelago. The majority of these speakers are inhabitants of the largest of the southern islands of the archipelago, Haŋŋo-Dze. The coastline of these islands is dominated by the Tsi decapolis, which taken as a whole have historically dominated trade both within the archipelago and (more importantly) from the archipelago out to the rest of the world. The cities are all to some extent differentiated from one another dialectally, particularly the oldest cities. The inhabitants of the smaller rural settlements are famous for their distinctive and bizarre ways of speaking, which are a constant source of jokes for the urban classes. With the expansion of the empire, Tsi-speaking colonies have also sprung up in far-flung places, all of which are gradually developing their own ways of speaking - particularly with the adoption of Tsi by local elites.