Oscan was spoken by a number of tribes, including the Samnites, the Aurunci (Ausones), and the Sidicini. The latter two tribes were often grouped under the name "Osci". The Oscan group is part of the Osco-Umbrian or Sabellic family, and includes the Oscan language and three variants (Hernican, Marrucinian and Paelignian) known only from inscriptions left by the Hernici, Marrucini and Paeligni, minor tribes of eastern central Italy. The language was spoken from approximately 500 BC to AD 100.
Oscan had much in common with Latin, though there are also many striking differences, and many common word-groups in Latin were absent or represented by entirely different forms. For example, Latin volo, velle, volui, and other such forms from the Proto-Indo-European root *wel ('to will') were represented by words derived from *gher ('to desire'): Oscan herest ('(s)he shall want, (s)he shall desire', English cognate 'yearn') as opposed to Latin vult (id.). Latin locus (place) was absent and represented by the hapax slaagid (place), which Italian linguist Alberto Manco has recently linked to a surviving local toponym.
In phonology too, Oscan exhibited a number of clear differences from Latin: thus, Oscan 'p' in place of Latin 'qu' (Osc. pis, Lat. quis) (compare the similar P-Celtic/Q-Celtic cleavage in the Celtic languages); 'b' in place of Latin 'v'; medial 'f' in contrast to Latin 'b' or 'd' (Osc. mefiai, Lat. mediae).
Oscan is considered to be the most conservative of all the known Italic languages, and among attested Indo-European languages it is rivaled only by Greek in the retention of the inherited vowel system with the diphthongs intact.
The Z of the native alphabet is pronounced . The letters Ú and Í are "differentiations" of U and I, and do not appear in the oldest writings. The Ú represents an o-sound, and Í is a tense . Doubling of vowels was used to denote length but a long I is written IÍ.