TextToSpeech

Internet Permission of Android Manifest are need to be added 

<uses-permission android:name="android.permission.INTERNET"/>

Below is the complete code for the activity_main.xml file. 

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout 

    xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:app="http://schemas.android.com/apk/res-auto"

    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical"

    android:layout_margin="30dp"

    tools:context=".MainActivity">

    <!--To add text in the app-->

    <EditText

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:id="@+id/Text"

        android:layout_marginBottom="20dp"

        android:hint="Enter Any Sentence"

        android:gravity="center"

        android:textSize="16dp"/>

    <!--when you press this button it will 

        convert text into speech-->

    <Button

        android:layout_width="wrap_content"

        android:id="@+id/btnText"

        android:layout_height="wrap_content"

        android:text="Click Here"

        android:layout_gravity="center"/>

    <!--To display the name of GeeksForGeeks -->

    <TextView

        android:id="@+id/textView"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:layout_marginTop="70dp"

        android:gravity="center_horizontal"

        android:text="GEEKSFORGEEKS"

        android:textColor="@android:color/holo_green_dark"

        android:textSize="36sp" />

</LinearLayout>

 Below is the complete code for the MainActivity.java file. 

package com.gfg.android_convert_text_speech;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;

import android.speech.tts.TextToSpeech;

import android.view.View;

import android.widget.Button;

import android.widget.EditText;

import java.util.Locale;

public class MainActivity extends AppCompatActivity {

    EditText Text;

    Button btnText;

    TextToSpeech textToSpeech;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        Text = findViewById(R.id.Text);

        btnText = findViewById(R.id.btnText);

        // create an object textToSpeech and adding features into it

        textToSpeech = new TextToSpeech(getApplicationContext(), new TextToSpeech.OnInitListener() {

            @Override

            public void onInit(int i) {

                // if No error is found then only it will run

                if(i!=TextToSpeech.ERROR){

                    // To Choose language of speech

                    textToSpeech.setLanguage(Locale.UK);

                }

            }

        });

        // Adding OnClickListener

        btnText.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View view) {

                textToSpeech.speak(Text.getText().toString(),TextToSpeech.QUEUE_FLUSH,null);

            }

        });

    }

}

The user may choose another language as well. For that refer to the below image to see how to do that.