Rather, the Mishnah is not particular with regard to this matter, and there is no consistent pattern. Sometimes it explains first that subject with which it began, and sometimes it explains first that subject with which the introductory line in the Mishnah finished. And if you wish, say an alternate explanation of the order of the Mishnah here: With regard to intimations, since they are derived from the exposition of verses and are not explicitly mentioned in the Torah, the tanna cherishes them and explains them first.
וליפתח הדין ברישא! מיפתח פתח בכינויין דאורייתא ברישא, והדר מפרש ידות דאתיין ליה מדרשא.
The Talmud asks: If so, let him begin the Mishnah with that, i.e., intimations, first. The Talmud answers: The tanna begins with substitutes for the language of vows, which are written in the Torah, in the first clause, and then explains intimations, which are derived from the exposition of verses.
הניחא למאן דאמר כינויין לשון נכרים הן. אלא למאן דאמר לשון שבדו להן חכמים להיות נודר בו, מאי איכא למימר?
The Talmud asks: This works out well according to the one who said that substitutes for the language of vows are terms for vows in a foreign language. Consequently, they may be considered to have been written in the Torah, as vows are certainly valid regardless of the language in which they are expressed. However, according to the one who says that these substitute terms are simply language that the rabbis invented for one to use in taking a vow so as to minimize using God’s name in expressing a vow, what can be said? These include novelties just as intimations do.
מי קתני ידות? ולאו חסורי קא מחסרת לה? אקדים נמי ותני ידות: כל ידות נדרים כנדרים, וכל כינויי נדרים כנדרים, ואלו הן ידות: האומר לחבירו, ואלו הן כינויין: קונם, קונח, קונס.
The Talmud responds: Does the Mishnah explicitly teach the halakha of intimations of vows? Do you not consider it incomplete, missing the phrase that mentions intimations? Once you are inserting this phrase into the Mishnah, you can also have it precede the clause about substitutes for the language of vows and teach the halakha of intimations at the beginning, so that the Mishnah reads as follows: All intimations of vows are like vows, and all substitutes for the language of vows are like vows. And these are intimations: One who says to his fellow: I am avowed from you, etc. And these are substitutes for the language of vows: Konam, konaḥ, konas.