Andrew Barry has suggested that Job 42:7, which reads:
חרה אפי בך ובשני רעיך כי לא דברתם אלי נכונה כעבדי איוב
ought to be rendered thus:
My anger burns against you and against your two friends, for you have not spoken to me what is right, as my servant Job has.
The significant difference to most interpretations and translations is the “spoken to” in place of “spoken about.” Andrew’s suggestion is based on the observation that the Hebrew here, כי לא דברתם אלי, employs the preposition אל following the verb דבר which elsewhere almost always means “speak to.” Consequently, Andrew reads Job 42:7 as referring to prayer — to speech directed to God, not discussions about him.
Grammatically and statistically the reading “spoke to me” is both possible and well attested — indeed, even at the beginning of Job 42:7 we have an instance of דבר + אל describing Yhwh’s speaking to Job (דבר יהוה … אל איוב). As Andrew points out, the majority of uses of the verb דבר in the piel followed by the preposition אל mean “speak to.” Nonetheless, there are a few exceptions such as 2Chron 32:19; Jer 28:16; 33:14; 51:12 (although outside Job 42:7–8 there are no exceptions within Job).
In light of these observations, what reasons can be offered in support of the more common/traditional rendering? None of the commentaries I have at hand offer any discussion of the point, but I think a case can be made for the common understanding:
1. There is some indication of mixing of אל and על in BH, particularly later texts (although על tends to replace אל, not the other way around). על would more clearly mean “speak about.”
2. There are examples where דבר + אל does mean “speak about,” so it is a possibility (see above). We can’t simply go on statistics or else all language would be impossibly wooden — it simply doesn’t work that way.
3. The LXX translates the preposition with ενωπιον rather than with εις, προς or a dative, suggesting that the early translators read it as God rebuking Job’s friends for what they had said about him rather than to him.
4. Perhaps the strongest point in favour of the traditional reading, however, is the context. Context plays a far more important role in determining the appropriate meaning of words than should statistics, after all. Within the book of Job, Job’s friends had not spoken to God at all, so to rebuke them for not saying the right thing to God seems odd. OTOH, they had made lots of claims about God, specifically about his response to sin and so made him the cause of Job’s suffering and made the reason some supposed transgression on Job’s part.
Furthermore, there are few examples where Job is recorded as speaking to Yhwh. Andrew points to Job 1:21 which is perhaps one of the few actual occasions where Job is recorded addressing Yhwh (although in 1:21 he does so rather circuitously). In Job 5:8 Job expresses his desire to present his case to God (and do so by speaking to him). Job’s desire to speak with God is manifest in the speech cycles of Job 4–27, but that’s not quite speaking to God either. In fact, Job isn’t recorded as directly addressing God until Yhwh himself calls for a response from him and he replies in Job 40:4–5. At that point, Job’s words to Yhwh amount to an admission of his ignorance in light of Yhwh’s array of questions which all highlight Job’s lack of knowledge.
Consequently, Job 42:7 may well be indicating that God approves of Job’s words to him admitting his limits, while Job’s friends all proceeded from the point of view that they held certain knowledge which they then sought to apply to Job’s sufferings — information which we know (from the prologue) to be ill-informed (at least in Job’s case).
As to whether the book is about prayer, I don’t think that is correct. Certainly it has something to say about how we should pray, about the importance of prayer, and so about prayer. But this is not the main message of the book. Nor, for that matter, is suffering.