To'ul'h language thought to have originated around 30,000 BT, traditionally used in record keeping and for intercultural and international communication. To'ul'ho'lo'ss (the ancestor of To'ul'hoss), formed a common language and an associated meta-culture of knowledge; a way for scholars across the ages to communicate with one another, as well as for To'ul'h traders and diplomats from distant regions to carry out their business. Though most To'ul'h cultures speak To'ul'hoss with local variants and accents, the written form has remained stable through To'ul'h history. This language had the status that Sanskrit, or Latin, or the written form of Chinese, assumed in Old Earth's human societies, but it was even more influential and eventually became universal on To'ul'h Prime. Texts that are thousands of years old can still be read by educated To'ul'h, and written history in the braille-like texts favored by the To'ul'hoss speakers extends back tens of thousands of years.
The written forms of the language are designed to be detectable by touch or by sonar: glyphs or ideographs carved into a surface, or runic inscriptions, or braille-like bumps and hollows, depending on the environment and culture. Scribes write in clay, carve symbols into stone, implant pegs or metal wire into softer surfaces, or use other methods to record information. Decorative inscriptions are usually intended to be pleasing to the touch, or to give interesting patterns when scanned with a sonar chirp.
A pidgin version of spoken To'ul'hoss is used among various post-To'ul'h clades or any Terragen clades adapted to speak and perceive the language.