今天的《词汇大师》讨论的是合成法compounding，合成词汇是未来主要的词汇组成方式之一，合成词有着一定的规则，例如：一般情况下，合成词的属性和其靠后的组成成分相同……

AA: I'm Avi Arditti. Rosanne Skirble is away, but joining me from Los Angeles is English teacher Lida Baker to explain our topic on Wordmaster this week. It's a feature of the language called compounding.

LIDA BAKER: "Compounding is when we take two words in English and we put them together to make a brand-new word. For example, you can take the word race and the word car and you can put it together and you have a race car. But interestingly you can also combine those two words together in the opposite order, car plus race. And then you have ... "

AA: "Car race."

LIDA BAKER: "Car race, which is a kind of ... "

AA: "Race."

LIDA BAKER: "Isn't that interesting? So a race car is a kind of car and a car race is a kind of race. One of the rules, I guess, of the meaning of compounds in English is that the core meaning is the word on the right."

AA: "So what are some other examples?"

LIDA BAKER: "Well, there are all kinds of compounds in English. The most common ones are when we combine two nouns — so race car, housekeeper. One of the things that's confusing about compounds is the spelling, because sometimes it's written as two words; for example, race car. Sometimes it's written as one word; for example, housekeeper. And sometimes it's written with a hyphen. I actually would have to check this myself, but I think the word baby-sitter is written with a hyphen.

"Now the point is, even native speakers of English don't always know how to spell compounds and they have to consult a dictionary. So I would give my students exactly the same advice. "Now let's move away from the written language and talk about the spoken language. There is a unique feature of compounds which is that the first word is normally the one — well, always the one that is stressed. So notice, for example, that we say RACE car, HOUSE keeper, BLACK bird, MAKE up, BABY sitter. You see how the first — we've talked on this program about word stress before. In a compound the first word is the one that gets stressed, and that's one of the things that actually identities it as a compound. What if you have, for example — well, where does the president of the United States live?"

AA: "In the White House."

LIDA BAKER: "In the WHITE House, and it's stressed on the first word. But I live in a white HOUSE. So there's a difference between a compound which is a unit that has a meaning of its own, like White House, which is the residence of the president of the United States, as opposed to a house that happens to be white. Another famous example of that is blackbird, which is a specific type of bird, and a black bird as opposed to a blue bird or a red bird, you see?

AA: "Uh-huh."

LIDA BAKER: "So what we have to do in the classroom — first of all, explain to students what I just explained to you, and then do what we call ear training. I can propose a couple of activities that teachers can do that can help students to learn compounds. One of them is a simple matching activity where you have two columns. And what the students have to do is take a word from the first column and match it with a word in the second column and create the compound and then practice saying it correctly. So, a simple matching activity.

"But there's another activity that is really fun, and that is to take these — you know how we were talking about the difference between 'White House' and 'white house' or 'blackbird' and 'black bird'? You take those phrases and you try to create — this is kind of for advanced students — but try to make one sentence that contains both of those. So as an example: 'I saw a white house on my way to the White House?' Can you hear the difference?"

AA: "Uh-huh."

LIDA BAKER: "Or I saw a black bird, but I'm not sure if it's a blackbird.' I've done this and it's a lot of fun. You see students, you know, they're pounding on the desk trying to figure out where the stressed word is and so on."

AA: Lida Baker is working on a new listening book for English learners, and she teaches in the American Language Center at the University of California, Los Angeles.

That's all for Wordmaster this week. Our e-mail address is word@voanews.com. And all of our segments can be found online at voanews.com/wordmaster. I'm Avi Arditti.

MUSIC: "Blackbird"/Beatles