Maybe you can adapt this. The macro assumes the page numbers are in the
built-in "Page Number" character style, and you replace them with your own
"EthiopianNumber" character style, which sets your Ethiopian font.
It uses a wildcard Find to match (arab) numbers, and assumes they're all
below 2000, or you'll get an error message when replacing.

Dim i As Long
Dim a(1, 2000)  ' your lookup table
For i = 0 To 2000
  a(0, i) = Trim(STR(i))
  ' store the ethiopian number in a(1,i), instead of the next line:
  a(1, i) = Trim(STR(2 * i))
Next i
Selection.HomeKey Unit:=wdStory
Selection.Find.ClearFormatting
Selection.Find.Replacement.ClearFormatting
Selection.Find.Style = ActiveDocument.Styles(wdStylePageNumber)
Do
  With Selection.Find
     .Text = "[0-9]{1;}"
     .Replacement.Text = ""
     .Forward = True
     .Wrap = wdFindContinue
     .Format = True
     .MatchWildcards = True
  End With
  If Selection.Find.Execute Then
     Selection.Style = ActiveDocument.Styles("EthiopianNumber")
     Selection.Text = a(1, Val(Selection.Text))
  Else
     MsgBox "Done", vbInformation
     Exit Sub
  End If
Loop

Regards,
Klaus

If Ethiopian numerals the ones where you have different characters for
1-10,20,30,...,90,100 and so on, I think you will have a problem here if
your page numbers are inserted using { PAGE } fields in a header or footer,
because
a. you can't simply change the font of the { PAGE } field result using a
\*Charformat switch
b. unless every page is in a separate Word section, you won't be able to
replace the { PAGE } result by a different number on each page, because the
same header/footer is used for the whole section.

What you can do is
a. create Word Document variables with names such as

e1
e2
e3

and the corresponding strings required for the numerals
b. instead of PAGE fields, use the following nested fields:

{ DOCVARIABLE "e{ PAGE }" \*Charformat }
c. if necessary, format the D of Docvariable with the font you need to use

All the {} need to be the special field code braces you can insert using
ctrl-F9.

Also, you probably have many references to those page numbers - how to deal
with those probably depends on how you are making the references.

Peter Jamieson