Seshto was the the primary language form in use for communications by the Tezwan civilization, on the planet Tezwa, in the 24th century. (TNG novel: A Time to Heal)

Languages

Altar • Andorian languages (Andorii • Graalen/Graalek • Greater Andorian • Lesser Andorian) • Bajoran (Old Bajoran • Old High Bajoran) • Beta Promethean • Earth languages (Anglo-Saxon • Celtic • English • Farsi • French • Gaelic • German • Greek • Hebrew/Yiddish • Italian • Japanese • Latin • Mandarin • Russian • Spanish • Swahili) • Esperanta • Federation Standard (Galacta) • Ferengi (Trading Tongue) • Galacta (Federation Standard) • Gorn • Grennai • Klingonese (Klingonaase • Kumburan • Rumaiyn • ta'Hol • tlhIngan Hol/pIQaD • Warrior's Tongue) • Makaro • Nemar • Old Hebitian • Old High Martian • Old Illyan • Olisu • Omearan • Orion language (High Orion • Kolari • Low Orion • Trader's Tongue/Trader's Script • Yrevish) • Orishan • Paklit • Payav • Pe • Realm Dialect • Reman • Romulan (Rihannsu • Old High Rihannsu) • Seshto • Taklathi • Tarn • Tellaran (Civil Conversation) • Tholian • Vegan • Vulcan (Ancient Vulcan • High Tongue • Old High Vulcan) • Xenexian • Xlatitigu