RS: Our guest is Hoyt Bleakley, an economist at the University of Chicago. He and Aimee Chin at the University of Houston have studied the effects of age on the earnings of immigrants to the United States.

HOYT BLEAKLEY: "We found when we looked at people who had come to the country, when they were brought as children by their parents, that it had a substantial impact -- on the order of, using our design, looking at numbers like ten, fifteen, twenty percent differences between people who were brought early enough that they could acquire English at essentially a native level, versus people who were brought later.

"The idea is that before puberty, certain maturation changes happen in your brain that makes it more difficult to learn language, makes it sort of almost impossible to get, to acquire the language to the point where you have no accent, but even difficulty in understanding the grammatical structures and acquiring vocabulary. And, as I say, this happens sometimes before puberty, different ages for different people, but maybe nine, ten, eleven isn't such a bad number."RS: "What message, would you say, does this have for the public policy debate about the teaching of English as a foreign or second language in our public schools?"HOYT BLEAKLEY: "When you consider that a difference of five or so years makes a difference of five to ten to fifteen percent in your wages and also, in effect, makes that person a first-generation instead of a second-generation immigrant -- then policies that can accelerate the process by which families with children can come into the country at younger ages I think are worth considering.

"So I would suggest that a lot of the people who are here who haven't really been able to learn, it's maybe because it's very difficult for them to do so. Why else would they apparently leave this money on the table and not decide to learn it facing these big incentives?"RS: "The incentive is there, but if they can't speak the language, they can't get the jobs."HOYT BLEAKLEY: "That's right. And so part of the kind of compact or bargain that traditionally we've had with regard to immigrants is that their children will be given a fair shot. And so a lot of people come maybe even accepting that their own status is going to be relatively low, but on the other hand their children will have these terrific opportunities.

"That actually ties into the second study that we've done which is actually looking at the group that we mentioned before, the sort of early and late 鈥?arrivers, and looking at their children. And the idea being: Is there something about being in a household that has a strong English speaker versus a weak English speaker which actually helps children in their realization as well, both educationally and in terms of integration into the language and culture of the U.S.?"AA: "And what did you find there?"HOYT BLEAKLEY: "There we find that even though these children are natives, of course a lot of their language environment comes from the home, and so they're enrolling in school with language deficiencies. And that's certainly an issue, maybe not in preschool or kindergarten where you're perhaps not learning anything besides social interaction. But once you start learning hard skills like arithmetic and reading and so forth in primary school, it's very important to really be up to speed on the language."RS: Hoyt Bleakley is a professor in the Graduate School of Business at the University of Chicago. The second study he mentioned is not yet published, but the first appeared in the Review of Economics and Statistics.

AA: Now to follow up on our recent segment about what to call people who are in the United States without following immigration laws -- which is currently classified as a civil rather than a criminal offense. We talked to linguist Otto Santa Ana at the University of California, Los Angeles. He says "illegal immigrant" is a biased political term, and that a neutral term like "undocumented immigrant" is better.

RS: Listener James Metcalf in Durban, South Africa, disagrees. He writes: "It's a long time since I heard such specious arguments, but it's the kind of thing one expects from left-of-center liberals from U.S. universities. It is illegal to enter the U.S. (or any other country) without proper permits. Ipso facto, they are therefore illegal immigrants."AA: And that's Wordmaster for this week. If you have a comment, or a question, we'd love to hear it. Write to [email protected]. And you can download all of our segments at voanews.com/wordmaster. With Rosanne Skirble, I'm Avi Arditti.