This is about the best I can do by way of providing a SSCCE:

1) files:

   a) title files (one title per file):
   
      title-001.tex
      title-002.tex
      ...
      title-999.tex

   b) catchfile index (one file of a thousand lines; a thousand titles is about three or four times the number needed):
   
      \CatchFileDef{\zerozerozero}{title-000.tex}{}
      \CatchFileDef{\zerozeroone}{title-001.tex}{}
      ...
      \CatchFileDef{\nineninenine}{title-999.tex}{}

   c) document files (several categories, having same title):

      article-001.tex
      article-002.tex
      ...
      article-003.tex

      abstract-001.tex
      abstract-002.tex
      ...
      abstract-003.tex

      catalogue-001.tex
      catalogue-002.tex
      ...
      catalogue-003.tex

2) In the head of each document file is a placeholder for the English representation of the serial number of the title: "\zerozerozero".  If the placeholder is not useful, I can delete it.

3) In the head of each document file is the serial number of the title, in Arabic representation: "No. 345".

4) The serial number of the title appears also in the filename of the document file:  "article-345".

5) The objective is to write in the document file the English representation of the serial number of the title:  "\threefourfive".

6) Once the English representations are in place, I can use Perl to make necessary adjustments.