Learn Romanian: Vă rog, așteptați aici!

Te rog is used when speaking to one person informally. Because this sentence is using the formal polite register, we use vă rog. Vă is the formal (and plural) version of te ('you').

What does vă rog actually translate to word-for-word?

It literally means 'I ask you'. The verb rog means 'I ask' (from the verb a ruga), and vă means 'you' (formal singular or plural). Romanian uses 'I ask you' as the standard way to say 'please'.

If I am politely telling one person to wait, why does așteptați end in -ți, which is the plural ending?

When you use the formal polite register (imagining the pronoun dumneavoastră), the verb must always take the 'you plural' form, even if you are only talking to one person! So așteptați is the correct form for both 'you all wait' and 'you (formal, singular) wait'.

Is așteptați a special command form of the verb?

For the formal 'you' (dumneavoastră) and the plural 'you' (voi), the command form is exactly the same as the normal present tense form. So așteptați can mean 'you are waiting' or, as a command in this sentence, 'wait!'.