— this is a draft encyclopedia entry —
Pro-drop is an abbreviation of “pronoun dropping.” It describes a feature of some languages that do not require an overt argument, especially a subject, to be present in a clause. That is, whereas English is not a pro-drop language and thus requires a subject noun or pronoun in a finite verbal clause like He has spoken, in Italian the overt subject may be “dropped,” Ha parlato ‘(He) has spoken’.