I watched the Apple guide and it mentions you can open Word documents that come as email attachments.

Can you save the document to your phone?
Can you bluetooth a Word document to the phone?

Also does the iPhone support different languages out of the box? If the Word document contains both English and Thai will the Thai show up on the iPhone?

Thanks in advance

You can open Word attachments via email, but you can't save the attachment to the iPhone. As for language support, I have no idea.

My understanding is that the newest firmware update will address at least part of the language issue.

Is the email/attachment stored on the phone or left on the server?

I just tried, and it seems to locally cache recently accessed attachments.

Otherwise, it looks to be totally random. After turning on Airplane Mode, I just accessed a 2 week old email with two photo attachments, and only one of the images appeared. The other one needs network access to view.

So if you're not online you may not be able to access old attachments?

If you have downloaded the message with the attachment, you can still open the attachment when your not online.

It's IMAP, so the attachment is on the phone and mailbox until it's deleted off