Purpose: The aims of this study were (a) to locate the breakpoints of a balanced translocation (7;13) within a mother (B) and daughter (T); (b) to describe the language and cognitive skills of B and T; and (c) to compare this profile with affected family members of the KE family who have a mutation within "FOXP2." Method: The breakpoint locations for T and B were identified by use of fluorescent in situ hybridization analysis followed by DNA sequencing using long-range polymer chain reaction amplification methods. The cognitive and language characteristics were obtained via the use of standardized tests of intelligence, receptive and expressive vocabulary and sentence use, and a spontaneous language sample. Results: The translocation breakpoints in T and B were found in "FOXP2" on chromosome 7 and in "RFC3" on chromosome 13. T and B's pattern of relative strengths and weaknesses across their cognitive and language performance was found to be similar to descriptions of the affected KE family members. Conclusions: Prior reports of individuals with chromosomal rearrangements of "FOXP2" have emphasized their speech impairment. This study provides additional evidence that language--in particular, grammar--is likely to be influenced by abnormalities of "FOXP2" function.