Mo at Neurophilosophy points to an interesting paper (which reads like a case study from Oliver Sack’s book):
After the rehabilitation period, a series of linguistic tests was administered to determine the extent of his speech deficits. M.H. exhibited deficits in both languages, but the most severe deficits were seen only in Hebrew. In this language he had a severe difficulty in recalling words and names, so that his speech was non-fluent and interrupted by frequent pauses. He had difficulty understanding others’ spoken Hebrew, and also had great difficulty reading and writing Hebrew. In Arabic, his native language, all of these abilities were affected only mildy. Differences were also seen in the effects of intensive language therapy. Although the therapy led to improvements in both languages, the improvements in Arabic were seen in all linguistic abilities; in Hebrew, by contrast, there was only mild improvement in his spontaneous speech and comprehension, and his ability to name objects remained unchanged.Similarly, his ability to read and write Arabic, but not Hebrew, improved significantly.
Take a look!