When you've never heard the spoken language, never heard the voices of your parents or other adults, never heard your own voice, then the national language is more difficult than a foreign language. It is as difficult as inaudible Chinese is to hearing people who don't know Chinese..
Many deaf people are not comfortable using a spoken language. They cannot speak it, they cannot hear it. Lipreading is very, very difficult and mostly a guessing game.
In school, deaf children learn to read and write. But with no or limited knowledge of the spoken language, learning to read and write is very difficult. You have to learn to read Chinese, with no or very limited prior knowledge of that language.
As a consequence, many deaf people are 'functionally illiterate'. They can read street signs, simple messages. But they have problems reading longer and/or more complicated texts.
When they write, they may use the word order that they use in sign language or they make mistakes with function words or tenses, because these cannot be translated 1-1 from sign language.
Do not assume that a deaf person has language problems when he/she makes mistakes in reading or writing or refuses to read and write. He or she is not dyslexic, is not an education drop-out or failure. He or she will be perfectly fine when a sign language is used. And no, unfortunately, there is no generally accepted writing system for sign languages. To make written texts accessible for deaf non-readers, texts have to be translated into sign language. If this is not possible, make sure that informational texts are easy to read:
- use relatively short sentences;
- keep words that belong together, close together in a sentence;
- use high-frequency words;
- if you have to use technical terms, jargon or abbreviations: explain what they mean, either in the text or in visually contrasting blocks of text or pictures;
- present your message in a way that is easy to visualise: as if you're writing a script for a movie. Where, when, who, what?
- break down long and/or complicated messages into shorter bits. Present these bits in a logical order;
- add subheadings that will visually break a longer story into smaller, easy to manage paragraphs;
- use subheadings that tell the reader what a paragraph is about.
- if possible: add a short 'intro' to chapters and sections, so that the reader can activate the correct prior knowledge;
- use a visually interesting, 'light' lay-out;
- add visuals to support or explain the meaning of paragraphs or words.