"I am shy about trying to speak Chinese?"=我说中文很害羞=wǒ shuo zhong wen hen hai xiu
"I can't say much in Chinese."=我不会说太多中文(wǒ bú huì shuō tài duō zhōng wén)=我只会说一点中文(wǒ zhǐ huǐ shuō yì diǎn zhōng wén )=我会说的中文不多(wǒ huì shuō de zhōng wén bù duō)
Hope it works~