Question

So I am try to write a script that will turn a to an (when necessary). And it is harder than I thought.

var txt = "This is a apple.";

var pos = txt.search(/a\s[aeiou]/i);
txt = pos != -1 ?
      txt.substring(0,pos+1) + "n" + txt.substring(pos+1,txt.length) :
      txt;
//"This is an apple."

It is working, but when I try "There are 60 minutes in a hour.", it didn’t not change it into an because of the regex. So I changed it:

var pos = txt.search(/a\s([aeiou]|hour)/i);

Now it is working (at least for “hour”). But now if I put "There are people in a university.", it will change it into an university, which is not correct.

So, is there a regular expression that can cover the rules of using a and an in the English language? Thanks!

Answer 1

There was a very good thread about this on StackOverflow a while ago: How can I correctly prefix a word with "a" and "an"?

Basically the consensus was that the best way involves a large dataset from which to learn, and the second-best way involves a pronunciation dictionary such as the CMU dict designed for speech synthesis.

To give an example from the CMU dict:

University comes out as:
Y UW N AH V ER S AH T IY . 

Umbrella is rendered as:
AH M B R EH L AH .