As a parent you have probably noticed that the days of your child "phoning home" (as ET would put it) seem to be behind us. Millennials HATE to talk on the phone.

This generation grew up with the gradual introduction of instant messaging, texting, email, and other forms of written communication. Because they’re just as instantaneous, but provide you the ability to think over your words, they’re more comfortable and precise communication forms. For a group of people dubbed “the anxious generation,” this is of the utmost importance. It could also be that phone calls require a kind of interruption to someone’s day, while text messages and emails can be opened and read at the recipient’s leisure.

Text messages for example are instant and mobile, meaning they can be sent and read at anytime. They also can be sent to multiple individuals at once, rather than making numerous phone calls.

Email provides more space than text messages, and are more leisurely, not as urgent as a text. Emails generally don't require the same "immediacy" as a text.

Over 205 billion emails are sent every day, or over 29 for every man, woman, and child on Earth.

For more on the fundamental advantages and disadvantages of each form of communication Forbes has a great informational article.