I imagine it would be tedious to do it that way.
I wonder if you could use the spell check dictionary from an open source project like Libreoffice, not sure what the format is but I imagine there must be a list of words in there in a format that would be easier to work with.
Upon quick search I found this:
https://github.com/wordset/wordset-dictionary
Might actually work, looks like it's in json format. I just tried to download one file and it's very unclean though. But there might be something else out there.
Whatever you get you will want to parse it out so you get just the words then you could load it up into SQL or maybe generate a big string array so it's built into the program as it's probably not data you're likely to change. Basically the jist would be to just generate a random number between 1 and how many words there are, and then load the corresponding one by index. I'd be tempted to create a custom data structure as it might be faster than just an array. Could make an interesting experiment. I would try the array first to see if it's acceptable.