There are several synonyms for the phrase "become shorter." Some commonly used alternatives include "shrink," "reduce," "diminish," and "truncate." These words can be used interchangeably to convey the idea of something becoming smaller in size or duration. Other synonyms include "abbreviate," "condense," "shorten," and "contract." These words can be used to describe a wide range of things, from the length of a garment to the lifespan of a product. Whether you are writing an academic paper, a news article, or a creative piece, using synonyms can help to vary your language and make your writing more engaging and dynamic.