Questions & Answers about Mój znajomy rozgadał się o tobie wczoraj.
How does the roz- ... się pattern change the meaning of the base verb gadać in this sentence?
The base verb gadać means to talk or chat. Adding the prefix roz- and the pronoun się adds momentum and intensity. It indicates that the subject started doing the action and got completely carried away or absorbed in it. So rozgadał się means he started talking and just couldn't stop.
Is rozgadał się a perfective or imperfective verb?
It is perfective. While the base verb gadać is imperfective, adding the prefix roz- creates a new perfective verb. It focuses on the completed action of entering into that intense, unstoppable state of talking. If you wanted to describe the ongoing process of getting carried away, you would use the imperfective equivalent rozgadywać się.
Why do we use tobie here instead of shorter pronoun forms like ci or cię?
The preposition o (when meaning "about") requires the locative case. The locative form of the pronoun ty (you) is tobie. The shorter forms are for different cases: cię is accusative or genitive, and ci is dative. After prepositions like o, you must always use the full locative form.
The word znajomy translates to "acquaintance," but it has an adjective ending. How does it decline?