'Have you been here long?' he asked conversationally.

“你来这里的时间长吗？”他攀谈式地问道。

I am at an unfavourable position in being conversationally unacquainted with English.

我由于不熟悉英语会话而处于不利地位。

They like you, you know, "he said conversationally."

“他们很喜欢你，你知道，”他攀谈道。

He's going to be giving me private lessons this year, said Harry conversationally.

“他今年要给我单独上课呢。”哈利引出了话题。

How is it possible to become conversationally fluent in one of these languages in 2-12 months?

怎么可能在2到12个月内就学用某种外语进行流利的对话？