Subtitlers can work intralingually, within the same language, or interlingually, across languages. Intralingual subtitlers create the subtitles for hearing-impaired viewers, whereas interlingual subtitlers create the subtitles for movies or television programmes in a different language to the one heard in the audiovisual production. They both ensure that the captions and subtitles are synchronised with the sound, images and dialogue of the audiovisual work.