In families with two working parents, fathers may have more impact on a child's language development than mothers, a new study suggests.
    Researchers __1__ 92 families from 11 child care centers before their children were a year old, interviewing each to establish income, level of education and child care arrangements. Overall, it was a group of well-educated middle-class families, with married parents both living in the home.
    When the children were 2, researchers videotaped them at home in free-play sessions with both parents, __2__ all of their speech. The study will appear in the November issue of The Journal of Applied Development of Psychology.
    The scientists measured the __3__ number of utterances (话语) of the parents, the number of diffe-rent words they used, the complexity of their sentences and other __4__ of their speech. On average, fathers spoke less than mothers did, but they did not differ in the length of utterances or proportion of questions asked.
    Finally, the researchers __5__ the children's speech at age 3, using a standardized language test. The only predictors of high scores on the test were the mother's level of education, the __6__ of child care and the number of different words the father used.
    The researchers are __7__ why the father's speech, and not the mother's, had an effect.
    "It's well __8__ that the mother's language does have an impact," said Nadya Pancsofar, the lead author of the study. It could be that the high-functioning mothers in the study had __9__ had a strong influence on their children's speech development, Ms. Pancsofar said, "or it may be that mothers are __10__ in a way we didn't measure in the study."

A. already   
B. analyzed    
C. aspects     
D. characters  
E. contributing
F. describing 
G. established  
H. quality     
I. quoted      
J. recording
K. recruited  
L. total       
M. unconscious 
N. unsure     
O. yet