This is a modal particle. These words change the atmosphere of a sentence and are often difficult to translate.
mal (colloquial short form of "einmal")
* Implication that one can not do something (at the moment), for example, in "Kannst du das mal machen?" ("I just do not have a hand free or time to do it myself.")
* Implication of an omission of the person spoken to, for example, in "Machst du das endlich mal?" ("How long do I have to wait?"). The person is impatient and emphazises this with the word 'mal'.
Depending on the context the meaning can slightly vary.
Ich frag mal - I will ask him (e.g. right away). As I said, it depends on the context.