This chapter deals with the study of how deaf and hearing signers, and others, understand sign languages by themselves and in relationship to other languages and modalities. By doing linguistic ethnography, it is possible to investigate these language attitudes and ideologies as they unfold in everyday practice, towards ideas such as the status of sign languages and particular varieties; discourses surrounding linguistic authority, authenticity and ownership; and the emergence (or development) of new sign languages and new subject-specific vocabulary. The methods discussed in this chapter are ethnographic research methods and visual methods: participant observation, ethnographic filmmaking, and language portraits. The main points of the chapter are illustrated by means of three case studies: (1) participant observation in multilingual tourist spaces in Bali, in which Indonesian Sign Language, International Sign, and American Sign Language are used; (2) ethnographic filmmaking within an international multi-sited research project focusing on International Sign; and (3) the use of language portraits with new signers and heritage signers in Flanders, who mostly use Flemish Sign Language and Dutch