Only skimed a couple posts, hope someone didn't already do this.

You can make the words have level modifiers on them. So, Singe (1) is worse than Singe (2) and Singe (3). Thus, if Singe (1) causes the spell to deal 1d3 damage, then Singe (2) would multiply that by 2, and Singe (3) would muliply by three, so on and so forth. Thus, just like with spells like Burning Hands and Shocking Grasp, among others, lower level "words" do more at higher levels.

This is interesting, though you would have to make certain sets of words, such as a line of "Singe" words, a line of "Cold" words, a line of "Shock" words, etc., and allow players to make up new words as per creating new spells.

I don't like the subdual damage thing, mostly because even with a d6 hit die, under your current set up, a first level mage usually doesn't get more than 2 least incantations. That is considerably less spells-per-day that a Sorcerer at the same level.

Since you're creating a language here, you could edit this language to have words with similar effects have similar spellings and pronunciations. So, the words for "singe", "scorch", "burn", "incinerate", etc. are all similar to each other. The same might be for the words "miracle" and "wish" or something.