Why Develop Pinyin for Mandarin Chinese?

There is simply no way to learn Chinese Mandarin characters other than memorising them. There is no way to know the meaning or pronunciation of a Chinese character when a person has never seen the character before.

Take this Mandarin Chinese character. How is anyone who doesn't read Mandarin supposed to know how it's pronounced. It's unique.

Pinyin is a system for transcribing Mandarin Chinese into a Latin based (Roman letters) alphabet. This allows people to pronounce and learn a Chinese Mandarin character they haven't seen before. 

The Pinyin letters create phonetic sounds that you can then relate to the Chinese character.