Checking grammar in strings

So I have a script where the user can type certain things in a text box and press enter to trigger the system to say something back, like an AI. The problem is, I have to type every possible thing a person can say with each form of grammer someone could use, such as with this line.

if(stringToEdit == “Hello” || stringToEdit == “hello” || stringToEdit == “Hey” || stringToEdit == “hey” || stringToEdit == “Hi” || stringToEdit == “hi”)

Is there an easier way to check if a person types “hello” where all forms of the grammar apply? Such as with caps or no caps? I hate having to write it every way a person could spell it.

Use string.ToLower to compare strings vs a set of lower case strings. This will create a new string when you do the conversion.

Or you can use a case insensitive string comparison with string.Compare.

To check if a string matches any of a set of strings, case insensitive, without allocating a new string object, you can do something like this using StringComparer.OrdinalIgnoreCase:

using UnityEngine;
using System;       // "StringComparerer" type
using System.Linq;  // "Contains" extension method

public class NewBehaviourScript : MonoBehaviour
    void Start()

    void Respond(string input)
        if (Synonyms.Hi(input))
            print("Hello to you too!");
        else if (Synonyms.Bye(input))
            print("Nice seeing you!");
            print("What you are on about?");

public static class Synonyms
    static string[] hi = { "Hello", "Hey", "Hi" };
    static string[] bye = { "Bye", "Seeya", "Good bye" };
    static StringComparer anyCase = StringComparer.OrdinalIgnoreCase;

    public static bool Hi(string input)
        // "Contains" test if input exist in hi, using anyCase
        return hi.Contains(input, anyCase);

    public static bool Bye(string input)
        // "Contains" test if input exist in bye, using anyCase
        return bye.Contains(input, anyCase);

You can use String.ToLower()

if(yourString.ToLower() == "hello") {
      //true if yourString is "Hello" or "hello"