There is no really satisfactory way to do this in Word, but for a text of
this length, a bit of handwork might give the results you want. You'll need
to set this up so that each page contains a certain number of whole
paragraphs of the corresponding language. Figure out, for any given page,
which is longer, the Latin or the English, and establish page break points
accordingly. For example, if four paragraphs of the Latin nearly fill a
page, and the English translation will also fit on a page, then that is
where you will have a page break. Once you've established your page break
points:
1. Insert your first pageful of Latin, followed by the corresponding page of
English. Repeat for each of the following pages.
2. If that's parallel enough for you, you can just insert page breaks and
call it done. If you want the individual paragraphs to be parallel, select
all the text and use Table | Convert | Text to Table, separating at
Paragraphs. Make sure that the dialog shows that the result will be a
one-column table.
3. Remove any borders Word may have added (Ctrl+Alt+U). Select the entire
table, go to the Row tab of Table Properties, and clear the check box for
"Allow rows to break across pages."
4. The next part will be rather tricky. Although you can display two pages
side by side in Print Layout view, they won't be facing pages, so you'll
have to do a bit of back and forth. For each paragraph, determine which is
longer, the Latin or the English, and set the height of that table row to an
Exact amount that will just accommodate it. Then set the height of the
corresponding row in the other language to the same height.