Hmm, given that "Silurian" seems to cover a number of sub-species, so there could be a lot of variation in direct communications; aural, including frequencies beyond human hearing, colour changes and body language come to mind.
However for durability and record keeping, unless there is some form of telepathic storage, then some form of 'offline' language would be necessary, otherwise information would be lost with the death of an individual. Then again this could be different to human writing, perhaps partially or entirely tactile rather than visual?
My AITAS files. Current projects: write-ups for 'Colonel' Thomas Blood, Mawdryn Reborn!, The Misfit Mob, the Iyteans, Professor Douglas Arthur, Coco's Delivery Service.
Scenario outlines for: The Mystery of the Monoliths, The Lord of Misrule, Cargo of Death and The Gorbals Vampire.