If a child uses some sign language to communicate, should the signed words be included in his vocabulary words, even if he does not speak them?
Yes, if a child communicates with sign language, their signed words should be included. So, for item 6 in the communication domain of the 16 month questionnaire, "Does your child say eight or more words in addition to 'Mama' and 'Dada'?", you can include both spoken words and signed words.
