I don't focus much in Dikduk but I had a cool insight on the Parsha of this week and I will share. After all, Dikduk and Safrut do go hand on hand.
The Vilna Gaon often times links the "trop" (cantilation sign) of words to their actual meaning. One famous example, in Shemot 1:13:
Many commentators explain that the Jews stayed in Egypt for less time because of the extreme hardship of their slavery. In the verse above, the Torah describes this hardship and the words have a cantillation sign called "Kadma Ve'azla". Says the Gaon that if you take the name of the cantillation literary it means "Anticipated and went" in Aramaic, indicating that because of the hardship of the slavery the Jews "anticipated and went" from Egypt before pre-set time. I heard this yesterday and I got excited about this kind of Dvar Torah and had the following insight:
In the coming week's Parsha, Shemini, I saw a very rare cantillation sign in the passage that speaks about Nadav and Avihu, the two sons of Aharon who died while doing work in the Mishkan. The Torah explains that they brought an....:
The rare "trop" below the word "Lo" is called Mercha Kefula or, alternatively, "Trei Ta'amei". Following the methodology of the Gaon, if we take the word "Trei Taamei" literary it means "Two Reasons" in Aramaic (I don't know the exact translation of the other name, Mercha Kefula, but Kefula also means two). The Talmud, mentioned by Rashi in this passage, says that there are two reasons why Nadav and Avihu died - either because they entered the Mishkan drunk or because they said an Halacha in front of Moshe, two actions that cause a death penalty. So here again, the trop gave us a hint about this passage.
Update: I refer you to Josh Waxman's piece on the Mercha Kefula, where he discusses this pshat and gives a broader perspective to this distinctive trop.