Language Skills Predict Integration Success
Observing Colorado refugees over a period of 5 years, the Refugee Survey & Evaluation (RISE) Study finds a correlation between a refugee’s language proficiency level and integration successes. Quote: (…) lack of English ability was pervasive among those with low integration. … Lack of English kept many with low integration isolated. As a result, American culture confounded them. Specifically, they had little direct experience or support from others in understanding and negotiating educational, social, medical, and government systems.
Lichtenstein, G., Puma, J., Engelman, A., Miller, M. (2016). The Refugee Survey & Evaluation (RISE) Study, Year 5: Final Report—A Study of Refugee Integration in Colorado.Unpublished technical report (pp. 1-126). Bluff, Utah, USA: Quality Evaluation Designs.

Refugees Learn English Over Time
After living in the country for more than 10 years, 86 percent of Somalis speak English at least “well,” and 61 percent speak English “very well” or exclusively. Among Hmong who are in the United States for more than 10 years, 67 percent speak English at least “well,” and 43 percent speak English “very well” or exclusively.
David Dyssegaard Kallick with Silva Mathema: Refugee Integration in the United States. June 2016.

English Skills Pay Off
Working-age LEP adults earn 25 to 40 percent less than their English proficient counterparts. While less educated overall than English proficient adults, most LEP adults have a high school diploma, and 15 percent hold a college degree. LEP workers concentrate in low-paying jobs and different industries than other workers.
Jill Wilson, Investing in English Skills: The Limited English Proficient Workforce in U.S. Metropolitan Areas. Brookings, 2014.

Refugees Have Lower English Skills, Compared to Other Migrants
Research shows that refugees, compared to migrants motivated by employment or family
reunification, have the lowest levels of destination language proficiency.
Barry R. Chiswick, and Paul W. Miller, Language Skills and Immigrant Adjustment: The Role of Immigration Policy. In Deborah A. Cobb-Clark and Siew-Ean Khoo, eds., Public Policy and Immigrant Settlement. (Cheltenham, United Kingdom: Edward Elgar Publishing, 2006).