As #Morsecode is rather slow, its practitioners have always used many abbreviations.
There are quite a few of them. Those, plus a rather limited set of select English words, enable two stations to exchange quite a bit of small talk: Introducing each op's name, location, basic info about local weather, and briefly introduce your station - all without knowing a common language.
"es" is short for "and", and "73" is the customary greeting at the end of a contact.