Here's why it's tricky:
* No universal "commoner language": Throughout history, there were no single languages spoken exclusively by commoners. The languages spoken by commoners were the same languages spoken by everyone in their community, including the elite.
* Different languages, different places: In ancient Rome, the commoners spoke Latin, just like the emperors. In medieval Europe, commoners spoke a variety of regional languages, such as Old French, Old English, and German.
* Dialects and variations: Within these languages, there were often significant differences in dialects and pronunciation depending on region, social class, and occupation.
* Latin and the Church: In many parts of Europe, even after the fall of the Roman Empire, Latin continued to be the language of the Church, education, and law, even among those who spoke vernacular languages.
To answer your question more effectively, I need more information. Tell me:
* What time period are you interested in?
* Which region or country are you curious about?
For example, if you want to know about the language spoken by commoners in England in the 14th century, I could tell you about Middle English and its variations.
Let me know, and I'll be happy to help you find the answer you are looking for!