However, it's important to note that:
* Latin was not a single, uniform language. There were regional dialects and variations in pronunciation and vocabulary. The Latin spoken in Herculaneum might have differed slightly from the Latin spoken in Rome or other parts of the empire.
* Vulgar Latin was the everyday language of the common people, while Classical Latin was the formal language of literature, law, and government. The people of Herculaneum likely used both Vulgar Latin and Classical Latin depending on the context.
* Other languages were also spoken in Herculaneum. Greeks lived in the area, and there were likely other languages spoken by immigrants and slaves.
While we can't be certain of the exact words they used, the evidence suggests that the people of Herculaneum primarily communicated using Latin.