homophonic characters
In the realm of restricted composition, there is Ernest V. Wright’s Gadsby, which avoids the most common letter ‘e’ in English.
In Chinese, there is this elementary passage which plays on the homophone issue of spoken Mandarin Chinese. Every character in the entire passage is pronounced “shi” (with varying tones), but nevertheless at this level the passage would make no sense if recited. But, written in the Classical Chinese idiom, the passage makes perfect sense when read visually (and isn’t particularly difficult to comprehend even for a modern reader).
《施氏食狮史》
石室诗士施氏，嗜狮，誓食十狮。施氏时时适市视狮。十时，适十狮适市。是时，适施氏适市。氏视是十狮，恃矢势，使是十狮逝世。氏拾是十狮尸，适石室。石室湿，氏使侍拭石室。石室拭，氏始试食是十狮。食时，始识是十狮，实十石狮尸。试释是事。
This is one demonstration that written Chinese can hold significant semantic content beyond phonetic value, a mechanism that has been key for tying together diverging spoken dialects over a thousand years.
