For years, the council has been talk about renovating the old town hall.

talk 是动词，意思是"谈论、讨论"。 about 是介词，表示"关于、有关"。 talk about 是一个常用短语，意思是"讨论、谈论（某事）"，在这里指"讨论翻修旧市政厅的计划"。