Believe it or not, the first sound babies typically make is "goo goo" or "gah gah". Because these aren't meaningful words in our language, we don't get excited about them! We don't say "goo goo" and "gah gah" back to our babies, so they simply stop saying these and replace them with the more often favored "mama" and "dada".
To encourage your baby's babbling, talk to your baby often! And when your baby talks, talk back. Language development can't be learned on a screen using an iPad or a television. It is too complex for that. The social context of language cannot be overlooked and can only be provided with face to face interaction.
It's perfectly natural to use "motherese" which is the rhythm and tone of speech that we instinctively use when we talk to our babies. This pattern of speech is great for infant language development as it draws attention to the sound patterns and individual sounds of words and phrases.