Middle CLT
The Pactspraecha is the language of the Pact era, roughly years two hundred to five hundred, which this wiki calls Middle CLT. See Lexicon:Middle for its words.
Long vowels, flowing endings, and a deliberate elegance, because the people speaking it were building a philosophy and wanted a tongue that sounded like one. Nearly every technical term still in use — the words of the Oathbond, the Pact, the Natural Order, the trades and the measures — was coined then, and the Modern dictionary's etymologies run through it: a Modern word is "from Middle" something, and the Middle word is "from Proto" something older.
The authority prefixes da- and ma- were taken up in this period, as the words to hand for authority willingly answered.