Obviously, Gulliver is a linguist. He spends a lot of time laboriously documenting all kinds of (completely made up) words, presumably to give himself some authority as a man who has actually visited the countries he describes. At the same time, Gulliver's Travels includes a lot of suspicion of the written word: the Houyhnhnms have no written language. And Gulliver's experiences on the island of Glubbdubdrib teach him that most written history is a pack of self-serving, vicious lies. And the Brobdingnagians specifically restrict the number of words that can be used to write a law to 20, so that lawmakers can't fall into jargon or confusing language. How weird is that, that a written book has all of these messages against writing?
Gulliver implies that, because Houyhnhnm histories are collective, they avoid profit seeking and factionalism that skew histories by "prostitute [human] writers."
Despite all of Gulliver's protests about the truth of his tale, by including parodies of other writing styles in Gulliver's own narration, Swift reminds us that Gulliver is a fictional character created for the purpose of satire.