Which is correct?

[mylevt]

Dear teacher.
Please show me which is correct.
1. He spoke too quietly to hear for the people at the back of the room.
2. He spoke too quietly for the people at the back of the room to hear.
Thanks a lot.

[Tdol]

The second is correct. The word order is wrong in the first.

[mylevt]

Dear Sir,
It is very kind of you to help me.
Thanks.

[M56]

The second is correct. The word order is wrong in the first.

How about:

He spoke too quietly to hear, for the people at the back of the room.

[Casiopea]

How about:

He spoke too quietly ?PRO to hear, for the people at the back of the room.

Possible, but the PRO, or empty syntactic subject for "to hear" is ambiguous. Does PRO refer back to "He" or refer forward to "the people"? Moreover, what's the subject doing after the PRO? Wouldn't it be clearer just to state the subject?

He spoke too quietly for the people at the back of the room to (be able to) hear (what he was saying).