Glosses are an attempt to write a sign language by arranging spoken language words in the grammar and syntax of the sign language, with each word corresponding to a sign.
The main problem with glosses is that sign languages include grammar elements (such as classifiers) which cannot be expressed in the words of a spoken language.
For instance, in American Sign Language the sign for HELP is known to have thirty-four variations, including "to help", "I help you", "you help me", "they help each other", or "they help us continuously".
Some of these variations are expressed in ASL using movements of the shoulder and torso, where the degree of movement indicates the magnitude of the meaning. These kinds of subtle differences in meaning can be accurately recorded with SignWriting, but not with glosses.