Is girl talk really just for girls? Not according to many sociolinguists. These culture-analyzers say that new features of a language, from the sound of "house" to the use of "so," often start with women.

A study of Canadians tracked the words "just," "like" and "so"—as in "I'm just, like, so there, you know?"—in teenage speech. Researcher Sali Tagliamonte of York University in Toronto found that "like" drops in popularity as teens age, but "so" and "just" stay in vogue. These two words, she concludes, are more than Valley Girl fads and seem fully entrenched in English.

Other studies have suggested that women are always at the linguistic cutting edge. Women brought new pronunciations to the French Alps, Philadelphia and Detroit—and even developed a New York accent a generation ahead of men.

Why are women ahead of the curve? They tend to communicate more cooperatively than men, some researchers say, and thus may pick up others' habits more quickly. Women, on average, also have stronger verbal skills than men. Some experts say women are more attuned to language and its quirks, given their primary role in caring for children and teaching them to speak. Men lag behind, perhaps because they are reluctant to copy women.

But gender alone can't account for all language change. Men occasionally start verbal trends. And future studies may reveal the influence of class, ethnicity or other factors.

Females sparked the following language changes, say sociolinguists:

• You—Women updated "ye" to "you" in 15th-century England.
• House—One Philadelphia woman seemed to jump-start a regional accent when she pronounced "house" as "hess."
• My name is Lauren?—In New Zealand, women are ushering in the spread of the "high-rising terminal," or a statement that's spoken like a question. In the 1970s, so-called Valley Girls started the trend in suburban Los Angeles.
• Glottal stops—Where an accent leaves out certain consonant sounds—so that "bottle" sounds like "bah-ull," as in some areas of the U.K.—the change is usually led by young women.
• Car—Women spread the strong pronunciation of "r" in New York, making a clear distinction between "cars" in New York and "cahs" in Boston.
• Monolingualism—Residents of the Hungarian enclave in Oberwart, Austria, spoke both Hungarian and German—until the 1970s, when young women moved the community to monolingualism.