Learn Turkish: Misafirimiz var.

Turkish doesn't use a direct verb for "to have." Instead, you use a structure that literally means "our [thing] exists." Misafir means guest, -imiz makes it "our guest," and var means "there is" or "exists." So, misafirimiz var literally translates to "our guest exists."

How does the ending -imiz work on misafir?

The suffix -imiz means "our." Because misafir ends in a consonant and its last vowel is an i, Turkish vowel harmony rules tell us to use the -imiz form to make it sound smooth. If the word had a different last vowel, the suffix would change to match it.

The translation says "a guest," but I don't see the word for "a" (bir) in the Turkish sentence. Why?

In Turkish, you often don't need to use bir (a/an) when making a general statement about having something. Saying misafirimiz var focuses on the fact that you have company. Depending on the context, this could actually mean you have one guest or multiple guests!

If this can mean "we have company" in general, how would I specifically say "We have guests" (plural)?

You would add the plural suffix -ler to misafir before adding the possessive "our" suffix. It becomes misafirlerimiz var. However, in everyday conversation, the simpler misafirimiz var is extremely common when you just want to let someone know you have people over.