Also, in contrast to Epi-Olmec and later Maya stela, Izapa monuments rarely contain glyphs. Although this could imply that the Izapan culture lacked knowledge of any writing system, Julia Guernsey, author of a definitive work on Izapa sculpture, proposes instead that the monuments were intentionally language-free and that "Izapa's position at the juncture of two linguistic regions Mixe–Zoque and Maya may have fostered the penchant for non-verbal communicative strategies." Timothy Laughton, a British researcher, has provided a reading of the imagery and narrative depictions as one unified mythological whole, linking the mythology with the distribution of the monuments at the site.