Your shoelaces are untied
How can i say this in german?
Dein Schnürsenkel sind nicht zugebunden?
Firstly, you're using the familiar form of you/your - dein - and as "laces" are plural, you need the nomnative plural = deine ... with the E
If you don't know the person well enough to use du/dein, you should use the polite form of you/your - Sie / Ihre
Ihre Schnürsenkel sind ungebunden
Shoelaces, along with bread rolls and mugs, fall into the category of "things German has far too many words for". Wikipedia lists Schnürsenkel, Schnürbänder, Schnürriemen, Schuhriemen, Schuhnestel, Schuhbanderl, Schuhbändel, and Schuhbänder (some of them regionalisms). But as far as I can tell (from Wikipedia, dict.cc, and Google Trends) Schnürsenkel is by far the most common, with Schuhbänder coming in a distant second.