Stylise a string by doing multiple replacements at once and using extenstion methods. Unity3D

Whatever.cs

using UnityEngine;
using System.Collections;
using System.Linq;

namespace ExtensionMethods
{

    static class ElevenStringHelpers
    {
        // called as shown below

        public static string ReplaceAll(this string seed, char[] chars, char replacementCharacter)
        {
            return chars.Aggregate(seed, (str, cItem) => str.Replace(cItem, replacementCharacter));
        }

        //called like 
        // using ExtensionMethods;
        // "whatever".Elvenize();
        
        public static string Elvenize(this string seed)
        {

            char[] firstflip = new char[] { 'i', 'o' };
            char[] secondflip = new char[] { 'e', 'u' };

            return seed
                  .ReplaceAll(firstflip, (Random.value > 0.5f) ? 'e' : 'y')
                  .ReplaceAll(secondflip, (Random.value > 0.5f) ? 'a' : 'o');
        }
    }
}

consider
UnityEngine.Random.InitState((int)System.DateTime.Now.Ticks); or similar

This is just an example "Random" - and the default OOTB is not a very random one used improperly. feel free to replace