Telepathy and language are not only similar, they are intertwined in the learning process. When you were a newborn, you could not speak, but you had the ability to learn. Telepathically, you could recognize emotions, but little else. These emotions were all important to you, forming your perception of the world around you.
It was the affection you received, rather than the tender voice, that made you feel secure. It was the anger you received, rather than the harsh voice, that made you cry. In this way you learned to match the tones of voice you heard with the emotions they represented.
Two deaf parents once had a child. Because they could not speak, and because they lived in an isolated area, they kept their television on so that their chld could hear the voices and learn to speak. Unfortunately, the child didn't learn to speak even though he could hear perfectly.
The reason for this is that speech requires interaction to be learned. If the child spoke to the television, it did not answer. If the child signed to his parents, he received a response. Meaningless speech was abandoned in favor of sign language.
In this same way, children become telepathically deaf and mute. They experience no interaction on a telepathic level. Meaningless telepathy is abandoned in favor of speech.

Uh, yeah, sure. That's nice. Let's talk about something else...

If I'm telepathically deaf, how come I can hear you?