translating text in lua file

The thing is, I'm translating a game from English to Polish language. The text I'm trying to translate is in lua-files. I have most of the game translated, but I'm looking for a way to automatize replacing English text with Polish text. I have a few lua-files (which are very large), which contain code and text to translate, I have .txt files which contain sentences line-by-line in English language, which I want to have replaced in lua-files and I have same amount of other txt-files which contain sentences line-by-line (in the same order) in Polish language. I need help with a script which will take first line from english.txt, search for it in lua and, if found, replace it with first line from polish.txt, and then take 2nd line from english.txt, etc. I tried many applications, but none of them had this function. Someone advised me to use awk, grep or sed, but I didn't find out how to use them for my purpose. EDIT: Sorry. I forgot that the old files were .lua. Now it is .sjson