Errors attested in Celeian inscriptions are a reflection of Latin language that was actually spoken in everyday life by ordinary people. When studying Vulgar Latin, it is possible to observe the development of a language, which ended in Romance languages. Some attested mistakes are of a technical nature; but the greater part of them were made on account of the language development. Differences between the town and ager are expected more errors can be found in ager and these are of a greater importance; in the town they are mostly of a marginal character. It can be concluded that the town - Celeia itself - was romanized sooner and more comprehensively. The analysis of the vocabulary and linguistic peculiarities on the inscriptions of Celeia and its adjacent areas confirms the important role of the town, which became the center of Romanization for southern Noricum . Due to the character of inscriptions in the town as in ager there can be seen phonetic, spelling and morphological errors. Syntactic and discourse specifics and those connected with vocabulary are nothing more than isolated examples written in those few inscriptions, which none the less exceed rigid form of abbreviations and basic data. Monophtongizations, writings of letter K instead of C, simplifications of double consonants and vowels appear most frequently. These can be considered to be basic changes that arose in the language and left traces there through centuries.