Learn Icelandic: Ég á eftir að vaska upp. - I still have to wash the dishes.

The phrase eiga eftir að literally means "to have after to" or "to have left to" do something. You use it for pending actions. Here, ég á is "I have", so the whole phrase translates smoothly to "I still have to" or "I have yet to".

Can eiga eftir að also be used for the future tense?

Yes! Besides meaning you still have a task to do, eiga eftir að is very commonly used to express that something is going to happen in the future. For example, Það á eftir að vera gaman means "It is going to be fun." Context tells you which meaning applies here, since washing dishes is a pending chore.

Why use vaska upp instead of þvo for washing?

While þvo is the general verb for "to wash" (like washing clothes, cars, or yourself), vaska upp is a specific phrase used exclusively for washing the dishes. It is a loanword from Danish. You will also often see the noun form uppvask which means "the dirty dishes".

Why does the verb eiga become á here?

The verb eiga (to have, to own) is part of a group of highly irregular verbs. In the present tense for ég (I) and hann/hún/það (he/she/it), it changes to á. Remember that the "you" form is also irregular: þú átt.