"Jeg kender ikke det udtryk."

Translation: I do not know that expression.

[Synryo]

Does this mean a facial expression or a turn of phrase/idiom?

[Xneb]

It could be either without any context

[Urowarm]

For all practical use it means a verbal expression

[NormanNagy1]

Det udtryk kender jeg ikke. Would it be more everyday like? Just based on 'Det ved jeg ikke'.

[Martinsspiegel]

Should be a useful phrase for me!

[Lasse959880]

Sean and Mawa are both correct.

[Valentine123070]

"Udtryk" is my favourite Danish word so far. It just sounds funny :D