Gnommish is the "fairy language" used in the Artemis Fowl series by Eoin Colfer. It is not actually a language at all, but the English language encoded into a letter-substitution cipher where each symbol represents a letter. Lines of translatable Gnommish run along the bottoms of books one, two, four, five and six. However, in book one of the series, it is mentioned that one of the symbols was comparable to the Egyptian Anubis symbol. It is also mentioned that Gnommish is a mix of symbolic and alphabetic letters, running in spirals (but since reading in spirals gives most fairies migraines, most modern fairy script is arranged in horizontal lines).
A string of Gnommish symbols appears at the bottom of each page of Artemis Fowl. It comprises a substitution cipher which can be deciphered using sections of the book's text displayed in Gnommish, together with their English translations. A complete Gnommish cipher key can be found in The Artemis Fowl Files.
There are only five Gnommish words mentioned in the Artemis Fowl series. P'shóg is the Gnommish word for sprite, used in Book 1 by Artemis Fowl II while talking to the sprite in Ho Chi Minh City. He also uses the word ka-dalun, meaning fairy. D'Arvit is a Gnommish curse word. Book 1 declares after the first appearance of the word "D'Arvit" that, "There is no point translating that word as it would have to be censored." It is often used in the series to replace real profanity, likely to be in the place of a swearword. In the books it is often used by Commander Root, but also by other characters. "D'Arvit" was not the creation of Eoin Colfer, as is popularly believed. On the Aran Islands (off the coast of Ireland) there is a legend in which a dark banshee would rip your soul from your body when you were alone, unless you were to utter the Irish word 'Dh'ábhoit' (pronounced daw-voyt). The word was anglicized during the conquest of Henry VIII and became 'D'Arvit', though the original meaning remains. The curse is mainly used in Gaeltacht (Irish-speaking) areas of Connacht but is seen as an Irish word everywhere (with its original spelling). In Book 6, Holly Short and Mulch Diggums share a quick conversation, which included the Gnommish word "cowpóg" which translates as 'moron'. Commander Root tends to use these words often in the book.
In Book 7, the Gnommish name for the ship in the Atlantic Ocean is ffurforfer, pronounced 'fourfourfour'. It means 'plunderer'. Also it is revealed that in Gnommish, for a conversion from a verb (for example, plunder- ffurfor) to a noun (plunderer- ffuforfer), the suffix -fer is added. It is noted that this is similar to the English way of adding the suffix -er, hence implying that one was derived from the other.