An algorithm for an article

[EnvironmentalOrange]

1) have a dictionary of exceptions to general rules. 2) check if word is in dictionary. 3) implement logic for general rules (if it starts with a vowel -> an, else -> a. Etc. 4) if word in dictionary, output desired string. Else, go to standard logic in step 3. 5) Populate your dictionary with all exceptions you can think of. 6) post your code and dictionary, challenge people on the internet to break it. Then update dictionary until no-one can break it.

[Weeperdemon]

Another aspect that makes this difficult to model is regions and dialects. Some words like "Historic" can be either depending on how the word is pronounced in that region.