I am trying to get to the bottom of Thai constructions which I can only gloss along the lines of:
(1) Because of the fact that her friends helped her escape prevented the soldiers from catching her;
(2) Because she was angry, she therefore refused to return it to him (where therefore just refers back to the fact that she was angry).
One explanation that occurs to me is that the words glossed as because and therefore do not express a relationship between clauses (and therefore are not conjunctions). Instead, they express the roles involved in a causative relationship, or in other words flag their respective clauses as causes or consequences. This makes it easy to infer the relationship without actually encoding it, which means that while you can just flag the cause and leave it to whoever you are speaking to to link it to the consequence via a process of causation, it is also open to you - while still flagging the cause - to use a causative construction to express the process itself (as in 1) or to flag the consequence separately (as in 2). Logically you may also be able to flag the cause, use a causative construction and flag the consequence, but I haven’t yet found out whether that’s the case.
If that’s the right analysis, I don’t know what to call the words glossed as because and therefore. Would they be prepositions? If so, are there any other instances of the object of a preposition doing double duty as the subject of a verb, which seems to be what is happening in (1)?
Since this has been bumped I'd like to update the Q:
On the back of BillJ's comment I discovered CEGL and the arguments that H&P make for regarding words like because as prepositions. As interesting as that is, it doesn't solve the basic problem in (1), which is that the verb prevented needs to take the complement of because as its subject if the sentence is going to make sense, and EN does not permit that - in EN the subject can only be the whole PP... so the real question is, what linguistic mechanisms could enable the verb to take just the complement of the preposition as its subject?
The recovery of the subject from within a dependent clause looks to me a bit like raising, and there is another similarity in that the connection between the derived subject and the verb seems less direct than in the expanded version, as can be seen by comparing:
Because of the fact that her friends helped her, that prevented the soliders from catching her
Because of the fact that her friends helped her, the soliders were prevented from catching her
For me the first of these is marginal but the second is OK - the difference seems to be that in the second version, the direct relationship between the (understood) subject and verb is broken. That seems to parallel the fact that in a raised object construction, the direct relationship between verb and object is broken.
As for (2), therefore is a connective adverb and it just seems to be one of its peculiarities that it cannot take a subordinated element as antecedent - compare nevertheless in, although he was tired, he nevertheless went on working, where the antecedent is just he was tired.