hehe, 2nd year psychology exams right now?

So, Psi > 2nd year > Psycholinguists > Communicative disorders > Aphasia

1 Since Aphasia is an aquired disorder, commonly due to an injury to the brain or following a stroke; A rise worldwide can't really be due to environmental factors. I would assume detection methods might be the cause of this 'surge'

ie: Better detection, higher number of reported cases (where the actual value has remained constant, we just see more of it)

2 This all comes under the study of localisation, in terms of the speach centres of the brain (+ a touch of neurophysics)

Basically: "A pattern termed differential recovery" was noticed by Obler in 1984. Bilingual aphasics were noted to display a different recovery pattern for each known language. More recent studies have shown that "both or all languages are impaired and recover in like manner, in proportion in how well they were known at the moment of the aphasia-producing event"

Common theories suggest this pattern is determined by how the brain has organised the language information:

"..In particular famous Lenneberg’s (1067) notion of the critical period in a second language learning; and of course proficiency. It looks like, from empirical observations, that what is learned could conceivably influence how ones brain was organized for it..." (and therefore how it is effected in the case of a severe trauma)

3 I don't know enough about that.. speech therapy?

The above are merely my opinions. Remember when dealing with psychology, and to a lesser degree Neurophsyics, you have to remember what is written may not be so. Everything is subject to interpretation!!