Learn Swedish: Vänta här!

For many verbs, you do drop the ending to find the stem (like att läsa becoming läs!). But vänta belongs to a large group of Swedish verbs where the stem naturally ends in an -a. For these verbs, the command form is exactly the same as the infinitive form: vänta!

Do I need to include a word for "you" when telling someone to wait?

No, just like in English, Swedish commands don't usually need a subject pronoun. You just start with the verb, so Vänta här! is a complete sentence without needing to add du or ni.

Why do we use här instead of hit? Don't both mean "here"?

In Swedish, här is used for location (staying in a place), while hit is used for destination (moving towards a place). Because waiting means staying in one spot rather than moving to a new one, we use här.

When would I use vänta på instead of just vänta?

You add på (for) when you want to specify who or what you are waiting for. For example, Vänta på mig! means "Wait for me!". Since this sentence just tells someone where to wait, we don't need på.