Questions & Answers about Niemand mag hier naar binnen, behalve ik.
Why is it behalve ik (except I) instead of behalve mij (except me)?
When using behalve (except), the pronoun usually matches the grammatical role of the word it refers back to. Here, it is comparing you to the subject of the sentence, niemand (nobody). Because it refers back to a subject, it requires the subject pronoun ik. English speakers usually say "except me", but in Dutch, it is conceptually like saying "Nobody may enter, except I [may enter]."
Where is the verb for "to go" or "to enter" in this sentence?
It has been left out because it is implied! In Dutch, when you use a modal verb like mogen (to be allowed to) alongside a clear directional phrase like naar binnen (inside), you do not need to add the actual verb of motion like gaan (to go) or komen (to come).
Could I just say hier binnen instead of hier naar binnen?
Not in this context. Binnen indicates that you are already inside (a fixed location), whereas naar binnen indicates movement or direction (going inside). Since this sentence is about the act of entering a space, you must use the directional naar binnen.
Why does hier come before naar binnen?