Changing Elements based off an Input Field answer

Long story short, heres the code I'm using. I'm trying to make it if a certain set of words are said, you will get different effects. I'm also using the Elements for the text so I was wondering if there was a way for it to detect what is in the Input Field and changing the element accordingly?

 using System;
 using UnityEngine;
 using UnityEngine.UI;
 using UnityStandardAssets.CrossPlatformInput;
 using UnityStandardAssets.Utility;
 using Random = UnityEngine.Random;
 
 
 public class DebateConversation     : MonoBehaviour {
 
     public GameObject neutral_Nagito;
     public GameObject diffuse_Nagito;
     public GameObject hello_Nagito;
     public GameObject ponder_Nagito;
     public GameObject scold_Nagito;
     public GameObject hmmm_Nagito;
     public GameObject angry_Nagito;
     public GameObject surprised_Nagito;
     public GameObject insane_Nagito;
 
     public InputField Contradiction_Text;
 
 
     public Button NextConv;
     public Button PrevConv;
     public Button Contradict;
     public Canvas Contra_Menu;
 
     public GameObject Ponderosa;
     public GameObject Ponderosa_D;
     public GameObject D_Trigger;
     public Canvas D_Conversation; 
     public Text textbox;
     public UnityStandardAssets.Characters.FirstPerson.FirstPersonController fpc;
     int i, j, testJ;
 
     public string[] speeches;
     public string[] Contradiction_bullet;
 
     void Start () {
         Ponderosa.SetActive (true);
         Contra_Menu.enabled = false;
         neutral_Nagito.SetActive (false);
         diffuse_Nagito.SetActive (false);
         hello_Nagito.SetActive (false);
         ponder_Nagito.SetActive (false);
         scold_Nagito.SetActive (false);
         hmmm_Nagito.SetActive (false);
         angry_Nagito.SetActive (false);
         surprised_Nagito.SetActive (false);
         insane_Nagito.SetActive (false);
 
         Cursor.visible = false;
         Cursor.lockState = CursorLockMode.Locked;
         D_Conversation.enabled = false;
         testJ = j;
 
 
 
 
 
         Button CDTbtn = Contradict.GetComponent<Button>();
         CDTbtn.onClick.AddListener(Contra_TaskOnClick);
 
         Button NXTbtn = NextConv.GetComponent<Button>();
         NXTbtn.onClick.AddListener(Next_TaskOnClick);
 
         Button PREbtn = PrevConv.GetComponent<Button>();
         PREbtn.onClick.AddListener(Prev_TaskOnClick);
     }
 
     // Update is called once per frame
     void Update () {
     }
 
 
 
     void OnTriggerStay(Collider other) {
         Debug.Log (other.name);
         if (other.name == "Detective Ponderosa" && Input.GetKeyDown (KeyCode.E)) {
             Ponderosa.SetActive (false);
             Cursor.visible = false;
             Cursor.lockState = CursorLockMode.Locked;
             fpc.enabled = false;
             D_Conversation.enabled = true;
         }
     }
 
     void Contra_TaskOnClick () {
 
     }
 
     void Next_TaskOnClick () {
 
         i++;
 
     }
 
     void Prev_TaskOnClick () {
 
         i--;    
 
     }    
 
 
 
     void FixedUpdate() {
         string Contradiction_Bullet = Contradiction_Text.text.ToString();
         if (D_Conversation.isActiveAndEnabled) {
             for (int j = 0; j < speeches [i].Length + 1; j++) {
                 textbox.text = speeches [i].Substring (0, j);
                 testJ = j;
             }
 
 
         }
         if ((testJ >= speeches[i].Length) && (Input.GetMouseButtonDown(0))) {
             i++;
         }
 
         if (i == 0) {
             hmmm_Nagito.SetActive (true);
         }
         if (i == 1) {
             hmmm_Nagito.SetActive(false);
             ponder_Nagito.SetActive (true);
         }
         if (i == 2) {
             ponder_Nagito.SetActive (false);
             surprised_Nagito.SetActive (true);
         }
         if (i == 3) {
             if (Contradiction_Bullet == "knife") {
                 i = 7;
             }
         }
         if (i == 4) {
 
         }
         if (i == 5) {
 
         }
         if (i == 6) {
             surprised_Nagito.SetActive (false);
             hmmm_Nagito.SetActive (true);
             i = 0;
         }
         if (i == 7) {
 
         }
         if (i == 8) {
 
         }
         if (i == 9) {
 
         }
         if (i == 10) {
 
         }
 
         if (i == speeches.Length) {
             Ponderosa.SetActive (true);
             Cursor.visible = false;
             Cursor.lockState = CursorLockMode.Locked;
             fpc.enabled = true;
             D_Conversation.enabled = false;
         }
         if ((i == speeches.Length) && (fpc.enabled = true)){
             i=0;
 
         }
     }
 
 
 }