affidavit

間が開いてしまいました。久しぶりの投稿です。
パリス・ヒルトンの弟コンラッド・ヒルトンが昨年の夏にロンドンからロサンゼルスの国際線で起こした騒ぎで逮捕されました。記事はCNNからの引用です。
affidavitはすでにブログで紹介された単語で「宣誓供述書」（『プログレッシブ英和中辞典』小学館）という意味ですが，今回はその語源について考えてみたいと思います。
cf. http://d.hatena.ne.jp/A30/20121119/1353328315
『リーダーズ英和辞典』（第2版，研究社）ではその語源をhe has stated on oathと説明しています。ラテン語の文法についてネットで調べてみると，ラテン語文法では完了形にする場合，動詞にvを付け，さらに人称を表す語尾をつけることがわかりました。三人称を表す語尾がitのため，affidavitはラテン語動詞のaffidoが三人称の完了形に活用されたものだということがわかります。（Koyamamoto）

Conrad Hilton charged with assaulting flight attendants, who cuffed him on plane
Los Angeles (CNN)Conrad Hilton, the younger brother of celebrity heiress Paris Hilton, allegedly threatened and intimidated flight attendants on a British Airways flight from London to Los Angeles last summer, using profanity, smoking in the bathroom and calling passengers "peasants," federal authorities charged this week.
... Hilton admitted to calling people "peasants" on the flight, but "Hilton denied having a confrontation with a flight attendant near the start of the flight but acknowledged having other issues with flight attendants," the affidavit said.
Hilton allegedly told the FBI agent: "I told all of them I could get all of their jobs taken away in less than thirty seconds," the affidavit said.
When Gates read the federal law to Hilton, he interrupted the FBI agent and stated: "I did intimidate. But, through defense. He came up to me with his nose," referring to a crew member, the affidavit said.
http://edition.cnn.com/2015/02/04/entertainment/conrad-hilton-assaulting-intimidating-flight-attendants-charge/index.html