Multiple find and replace in a word document

I want to do a series of find and replace operations. Unfortunately, the documents I have to work on are in Word (.docx) format so I cannot script this. These are book chapters so formatting is important (italics, bold, indentation, fonts), I cannot simply convert to plain text.

Say I have a list of (about 20 different) words as follows:

black
blue
yellow

The replacement I need to do is to add accents so I would have a list of replacements like this:

bláck
blúe
yéllow

Is there a way I can automate this in Word? I would be happy to use another piece of software. I would be even happier if I could do this on Linux using scripting tools (but I guess this is wishful thinking). I have access to Linux and Windows systems, MS Word and LibreOffice.

I found this thread in which a macro that does more or less what you need is suggested. Perhaps that will help.