Null subject parameter

Okay kiddo, so when we talk about sentences in English, we usually have a subject (that's the person or thing that's doing the action) and a verb (that's the action they're doing). But sometimes, in other languages like Spanish or Italian, they don't always put the subject in the sentence. They just assume you know from the context who the subject is.

So the "null subject parameter" is talking about whether or not a language allows you to leave out the subject in a sentence. Some languages, like Spanish or Italian, have a "pro-drop" parameter that allows you to leave out the subject if you want to. Other languages, like English or German, don't allow you to leave out the subject - you always have to have one in there.

Does that make sense, kiddo?