#1 The Skill of Visualization
As a child listens to an adult read aloud, he or she develops the ability to make mental pictures of what's happening in the story. Those mental pictures are what help the child remember what he/she has read or heard - reading comprehension. The ability to learn later in life is mostly dependent on one's ability to retain knowledge gained through reading, especially in higher education. For example, success in law school is mostly about independently reading and remembering tons of case law. Most professional fields involve some sort of continuing education. So it's important for children to develop and perfect this skill early - they'll be better at reading comprehension throughout primary school and beyond.
#2 Beneficial Neuronal Changes
A study by researchers at the Cincinnati Children’s Hospital Medical Center in Ohio discovered that reading to young children ages 3-5 causes a marked increase in neuron activity in the left side of the brain, an area that controls visual imaging, language, and reading comprehension. How the human brain works is still an area of ongoing research, but it's appears from these studies that young children need the developmental stimuli that reading aloud provides.
#3 Flow of Language
Young children need to be exposed to complex sentence structure, and everyday conversation generally won't provide this because that's not how people talk. Words and sentences are the bricks and mortar needed to build the case for an idea or answer to some problem. Expressing that problem, thinking through how to solve it, and trying different scenarios often involve the construction of complex sentences and throught patterns. When an adult reads a book to a child, the child gets exposed to the complex sentences, thought patterns, and storylines that might not be encountered much in daily life.
Sentences are just arrangments of worlds, and those who are good at arranging words are generally called good communicators. People need to understand and be able to use complex sentence structure in order to use language to express ideas, solve problems, and express themselves. Language is a tool for life, and children who learn how to use language for all its intended uses have a head start.
#4 Expression Through Written Form
Children must learn is how to express themselves in written form, as opposed to verbal form. Public schools invest tons of resources in teaching children to write through programs such as Young Authors, which is a school-wide creative writing competition. A child will write numerous papers thoughout his or her school career, including formal research papers. The goal is to teach children how to express themselves using written language, and it is an art that's hugely beneficial in adulthood. A lot depends on a person's ability to write - college admissions, college classes, retaining scholarship through college, resume cover letters, and there is the possibility that anyone can become a wealthy/successful author.
As a first step, children need to hear and process well constructed sentences. As they hear how ideas and storylines are crafted and reinforced though paragraphs and chapters, they'll be better prepared for that creative writing/persuasive essay assignment.
In everyday conversation, most people use a limited number of words. However, when writing people draw from a much larger pool of vocabulary words, which gives flavor and depth to sentences. Young children with developing brains need to be exposed to a wide variety of vocabulary words, and it's not enough for them just to study a word list. They need to hear how the words are used in context. Pretty soon they'll be able to start using those words in their own sentences.
Children generally like being read to; it's an enjoyable experience for them. Amid the den technology children today are surrounded by, having a parent or guardian read a good book is a welcome escape. You can read just about anything you want - chapter books, biographies, short stories. Books with no pictures are great because they encourage visualization (described above). Be creative and talk to your child about what books he or she is interested in. Be sure to include some of those in your reading list. For some more great info, check out Business Insider's article on reading to children. It's something parents should never neglect!