How to access a public string attached on a UI Button

I need to access the public string variable on the script that is attached on my UI button and also to concatenate it.

Just to be clear this is for a word game, I have 26 buttons that contains letters from A - Z and each button has its own string value for the letter (example: Button A has a string value of "a"). Then i want to concatenate the string values whenever the player is trying to create a word.

 using UnityEngine;
 using UnityEngine.UI;
 
 
 public class LetterTiles : MonoBehaviour {
 
     public string letter;
     public Text displayer;
     float addTime;
     string word;
 
     public GameObject tile;
     GameObject Tile;
     Vector3 scale = new Vector3(0.8f, 0.8f, 0);
 
     public void letterClick()
     {
 
         //wordBuild.currentWord += GetComponent(Type.GetType(letter));
         wordBuild.currentWord += GetComponent(letter);
         //wordBuild.currentWord += GetComponent<Button>;
         
         Debug.Log(wordBuild.currentWord);
 
     }
 
 }