Breakdown of ¿Los estudiantes están charlando o estudiando?
el estudiante
student
los
the (masculine plural)
estar
to be (location/state)
estudiar
to study
Questions & Answers about ¿Los estudiantes están charlando o estudiando?
Why do we use están instead of son for "are"?
How do we get the words charlando and estudiando?
These are called gerunds, which are the equivalent of "-ing" words in English. To make them for regular verbs that end in "-ar" like charlar (to chat) and estudiar (to study), you simply drop the "-ar" and add -ando.
In English we ask "Are the students...", so why doesn't the Spanish sentence start with Están?
In Spanish, you don't have to change the word order to ask a question. You can keep the normal statement order (Subject + Verb: Los estudiantes están...) and just add question marks and a questioning tone of voice. However, starting with ¿Están los estudiantes... is also completely correct!