Choice between "few" and "a few"

Hi. Please help. Which is correct? Let us pretend this person has recently arrived in China and only know a few words. I happen to think the word "few" is correct in the following sentence since it needs to say that he doesn't know enough words in Chinese, thus giving him trouble when the time for writing a note comes.

He could write only few/a few words in Chinese, so it gave him trouble when it comes to writing a simple note.