Arbitrariness

This polysyllabic word describes the relationship between the linguistic sign (a.k.a. the word) and the thing represented. When I talk about words, I usually mean the spoken word (and therefore how it sounds when you say it), but the written word, of course, also has an "arbitrary" relationship to what it represents. (I was reluctant to admit this and have always been way more interested in the spoken word.)

The relationship between "hedgehog" and the spiny mammal is completely inorganic, random, and not intrinsic—get it? We could call that spiny mammal a "Big Gulp," as long as we all agreed that's what we'd call it.

Now, once once you've decided what a linguistic sign is, you can't really change it, because by now, it's been culturally agreed upon. That still doesn't mean that deep down, a hedgehog is more of a "hedgehog" than a "Big Gulp." It just means that people have agreed to call it "hedgehog."

Langue

This little French piece of vocabulaire refers to the totally abstract arrangement of rules that makes up a signifying system. Hold up: I'll explain. In other words, langue (pronounced lahng) is language. As babies start to talk, they learn this system; in other words, language pre-exists its users. When you learn a language, it's like joining a club. You didn't make that club up yourself; it existed before you were part of it.

Langue was what really rocked my world, because langue involves all the abstract regulations and conventions that go into the grand whole of linguistic expression—what I call the semiotic system (translation: system of signs).

Not to complicate matters, but I studied language as it was used during one particular time period (that's called synchronic), not as it evolved and changed through time (that's called diachronic). I was mostly interested in abstract, unchanging rules.

Parole

No, I'm not referring to provisional release from prison. Parole is French for "speaking," and it refers to a specific use of langue. For me, parole refers to individual speech acts. When you say, "I'd like to supersize that," it's an instance of parole.

Without langue, the abstract set of rules behind a language, there would be no parole. "I'd like to supersize that" doesn't mean anything unless the person you're talking to has internalized the words and the grammar of that sentence.

Parole is like langue set into action. So, you can see that studying one without the other is like being a scholar of literature without looking at individual books.

Semiology

So, semiology this is the study of signs. You might also have heard the term "semiotics." Some people say semiology and semiotics are the same things; others try to find some difference between the two. Don't sweat it for now.

Anyway, this term is readily associated with yours truly, but I'm not trying to claim all of the glory for myself. Other folks who followed in my footsteps (e.g., Roland Barthes, Claude Lévi-Strauss, Julia Kristeva, Jean Baudrillard, and a bunch of others) were semiologists (not to be confused with seismologists) in their own right.

My big thing was language, but semiologists study all kinds of sign systems—from film and political speeches to facial expressions and tribal rituals. Semiology is a huge field, because there are all kinds of sign systems everywhere. My specific interest was in Structural Linguistics, but you can study fashion magazines and still be a semiologist, as long as you're focusing on the system of signs in a fashion magazine.

Signifier/Signified

Not sold separately. LOL! What I mean to say is that you really can't study signifier without signified, or signified without signifier. It's like a Reese's peanut butter cup: you can't separate the chocolate and the peanut butter. These two puppies make up a whole sign.

The signifier is the form of the sign—the sound. Different words sound different to the ear and are processed differently in the brain. Also, we recognize words in distinction to one another: "Cat" is "cat" because it's not "bat" or "hat," not because there's something inherently cat-like about the word "cat."

The signified is the other half of the sign—it's the concept that is being represented by the signifier. A very popular example is the word "open" on a shop sign. That word "open" is the signifier. The signified is the abstract concept that the signifier represents: in this case, it means that we can go in and purchase our much-needed toilet paper.