double Dutch 晦涩的言语（或文字）；莫名其妙的话

【例句】
This article's so full of jargon and it's just double Dutch to me.
这文章满篇术语，于我而言简直是天书。

Your conversation about linguistics was all double Dutch to me!
我一点儿也听不懂你们有关语言学的谈话。