These notes on plagiarism vs proper citation are adapted from:

• Gibaldi, Joseph. MLA Handbook for Writers of Research Papers. Fifth edition. New York: Modern Language Association of America, 1999. 30-33.

The examples particularly illustrate the need to cite sources even when one has paraphrased or condensed information from its wording in an original source.

To use another person's ideas or expressions in your writing without acknowledging the sources is to plagiarize. Plagiarism is intellectual theft . . . Forms of plagiarism include the failure to give appropriate acknowledgement when repeating another's wording or particularly apt phrase, when paraphrasing another's argument, or when presenting another's line of thinking. To guard against inadvertent plagiarism [English Section "Type B"], make and keep careful notes that distinguish between your own thoughts and the material you have collected from other sources.

The words and thoughts of others may certainly be used in your research papers, but the borrowed material must not seem to be your own work. Suppose, for example, that you want to use the material in the following passage, which appears on page 625 of an essay by Wendy Martin in the book Columbia Literary History of the United States.

Some of Dickinson's most powerful poems express her firmly held conviction that life cannot be fully comprehended without an understanding of death.

If you write the following sentence without any documentation, you have committed plagiarism:

Emily Dickinson strongly believed that we cannot understand life fully unless we also comprehend death.

But if you cite your source the material may be used:

As Wendy Martin has suggested, Emily Dickinson strongly believed that we cannot understand life unless we also comprehend death (625).

The source is indicated, in accordance with MLA [modern, in-text] style, by the name of the author and by a page reference in parentheses. The name refers the reader to the corresponding entry in the works-cited list, which appears at the end of the paper.

Martin, Wendy.  "Emily Dickinson."  Columbia Literary History of the United
     States.  Ed. Emory Elliott. New York: Columbia UP, 1988. 609-626.

Two more examples follow:

Original Source
Everyone uses the word language and everybody these days talks about culture [. . .]. "Languaculture" is a reminder, I hope, of the necessary connection between its two parts [...]. (Agar, Michael. Language Shock: Understanding the Culture of Conversation. New York: Morrow, 1994. 60.)

Plagiarism
At the intersection of language and culture lies a concept that we might call "languaculture."

Original Source
Humanity faces a quantum leap forward. It faces the deepest social upheaval and creative restructuring of all time. Without clearly recognizing it, we are engaged in building a remarkable civilization from the ground up. This is the meaning of the Third Wave.

Until now the human race has undergone two great waves of change, each one largely obliterating earlier cultures or civilizations and replacing them with ways of life inconceivable to those who came before. The First Wave of change — the agricultural revolution — took thousands of years to play itself out. The Second Wave — the rise of industrial civilization — took a mere hundred years. Today history is even more accelerative, and it is likely that the Third Wave will sweep across history and complete itself in a few decades. (Toffler, Alvin. The Third Wave. New York: Bantam, 1981. 10.)

Plagiarism
There have been two revolutionary periods of change in history: the agricultural revolution and the industrial revolution. The agricultural revolution determined the course of history for thousands of years; the industrial civilization lasted about a century. We are now on the threshold of a new period of revolutionary change, but this one may last for only a few decades.

In the first example, the student borrowed a specific term ("languaculture") without acknowledgement; in the second example, the student presented another's line of thinking without giving credit. The students could have avoided the charge of plagiarism by rewording slightly and inserting appropriate parenthetical [or other appropriate] documentation.

At the intersection of language and culture lies a concept that Michael Agar has called "languaculture" (60).

According to Alvin Toffler, there have been two revolutionary periods of change in history: the agricultural revolution and the industrial revolution. The agricultural revolution determined the course of history for thousands of years; the industrial civilization lasted about a century. We are now on the threshold of a new period of revolutionary change, but this one may last for only a few decades (10).

In each revision, the author's name refers the reader to the full description of the work in the Works Cited list at the end of the paper, and the parenthetical documentation identifies the location of the borrowed material in the work.

Agar, Michael.  Language Shock: Understanding the Culture of Conversation.
      New York: Morrow, 1994.

Toffler, Alvin.  The Third Wave.  New York: Bantam, 1981.