speak on something/somebody谈论某人或某事并以其作为谈论的主题
speak of something/somebody在谈论中提到了某人或某事
speak about something/somebody谈论某人或某事,没有主题
speak to somebody over something通过某种东西与某人谈话
argue和conflict都有争论争辩的意思,但是argue有及物动词的词性,conflict则没有
they are arguing with each other比较常用
conflict一般是用作冲突和矛盾