今天的《词汇大师》回复了许多听众来信，回答了大家关于英语发音，与英语书写方面的问题……

First broadcast: January 26, 2005

AA: I'm Avi Arditti with Rosanne Skirble, and this week on Wordmaster: we answer a couple of questions with help from English teacher Lida Baker in Los Angeles.

The first is from a listener who teaches physics at Hebei Normal University in China. Bill Zhao wants to know if all voiceless consonants should be pronounced as voiced consonants if they come right after the sound of "s." Voiced means the vocal chords vibrate. For example, in the word "sports," he hears people pronounce the "p" as a "b." Lida Baker has the explanation:

LIDA BAKER: " It's not actually a 'b,' but it has certain characteristics of a 'b,' and I'll tell you why that is.

"'S' is a voiceless sound and 'p' is a voiceless sound. The problem in a word like 'sport' is that the vowel after the 'p' is a voiced sound. All vowels are voiced sounds: oh, ah, ee, oo, right? So what happens when you have a voiceless sound like a 'p' next to a voiced sound like a vowel, to some people that 'p' is going to sound a little bit like a 'b.' And that's what Mr. Zhao is hearing. There's a little bit of crossover between the voiceless and the voiced sound because of the fact that they're neighbors in that word.

"But if you look in any dictionary at the phonetic spelling of a word like sport or scout, that voiceless sound is written phonetically as a voiceless sound — in other words, as a 'p' or a 't' or a 'k.' And dictionaries don't indicate that there is this kind of intermediate quality to the sound because native speakers don't hear that. O.K. The bottom line is, it is still a voiceless sound but it has qualities of a voiced sound because of the fact that the vowel comes after it.

"Now there is one exception which I'm sure Mr. Zhao was also aware of, which is the case where you have what is written as a 't' occurring between two vowels in a word like pretty, p-r-e-t-t-y, which in British English is pronounced pri-tee. But in American English that 't' changes into a 'd' sound and we say ... "

RS: "Pri-dee."

LIDA BAKER: "That's right, and the reason for that is that you have this voiceless 't' sound between two vowels.'

AA: "Wait, a voiceless 't' between two vowels, or is it — "

LIDA BAKER: "Well, don't think about the spelling. Think about the pronunciation: preh-tee. If I slow it down, I'm going to pronounce it as a 't.' But there's those two vowel sounds there — eh, ee — and the voiceless 'tuh' will change to a 'd' sound in American English because of the fact that the consonant is surrounded by two voiced sounds.

"And the voiced sounds around it overwhelm, if you will, the voiceless quality of the consonant, and in this case it changes to a 'd.' But that's as far as I know only true in most dialects of North American English and it certainly isn't true in British English and in a lot of other varieties of English around the world."

AA: The next question is from Atefeh in Iran. She's studying English literature at a university, and would like to know the difference between the abbreviation U.S.A. spelled with periods and U.S.A. spelled without periods. As Lida Baker explains, the only difference has to do with style.

LIDA BAKER: "The meaning is the same, and whether you use the periods or not is something that your writing teacher is going to tell you that she prefers for you to write it this way or that way. Or if you're a professional writer and you're working for a newspaper or a magazine, generally different publications have their own style guidelines and they will tell you how they want you to write it.

"I should point out for people who are in the university and writing papers that there are style manuals for different college fields. For example, there is the style manual of the American Psychological Association, the APA style manual ... Students who are majoring in psychology as well as other social sciences are required to follow the guidelines of that style manual when they write papers. In my writing classes, I don't care which way students do it, as long as they're consistent."

AA: Lida Baker teaches in the American Language Center at the University of California, Los Angeles, and writes textbooks for English learners.

That's all for Wordmaster this week. Our e-mail address is word@voanews.com, and our Web site is voanews.com/wordmaster. With Rosanne Skirble, I'm Avi Arditti.