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In page SignWriting:

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SignWriting was not the first writing system for sign languages, being preceded by Stokoe notation;[2] but it is the first to adequately represent facial expressions and shifts in posture, and to accommodate representation of series of signs longer than compound words and short phrases. It is the only system in regular use, used for example to publish college newsletters in American Sign Language, and has been used for captioning of YouTube videos.[citation needed]