Colors, Letters and Numbers

The app teach kids colors, capital letters, small letters and numbers age of between 2 and 4 years.
The main activity has four buttons colors, capital letters , small letters and numbers.
When user clicks Colors button open activity.
Colors's activity has two buttons (Next and Start) and ImageView.
When user clicks Next button the app shows the next color.
When user clicks Start button the app shows and read color name by voice alphabetical order at 5 seconds interval.
When user clicks Capital letters's or Small Letters's button open activity.
Capital letters's or Small Letters's activity has three buttons (Next, Start and Random) and ImageView.
When user clicks Next button the app shows the next letter.
When user clicks Start button the app shows and read letter name by voice alphabetical order at 5 seconds interval.
When user clicks Random button the app shows and reads letter by voice random order at 5 seconds interval.
When user clicks Number's button open activity.
Numbers's activity has three buttons (Next, Start and Random) and ImageView.
When user clicks Next button the app shows the next number.
When user clicks Start button the app shows and reads number by voice ascending order at 5 seconds interval.
When user clicks Random button the app shows and read number by voice random order at 5 seconds interval