The reason why the phone's input method couldn't be typed using Pinyin was probably because the character set in the input box didn't match. The input method that comes with a mobile phone is usually based on the mobile phone's operating system, and the mobile phone's operating system may not support certain character sets. For example, the operating system of a mobile phone might only support the Chinese character set and the input method that came with it might not support it. The solution was to change the character set of the input method or use another input method. He could also try to type in some basic Chinese characters in the input box to see if he could type them in the input method. If you still can't type some words, you may need to contact the phone manufacturer or input method developer for help.