I don't know if the known (canon) language uses any infixes (additions within a word) as opposed to pre- and suffixes. I don't think it does. But when you're looking at a very short word that is currently in the dictioary (canon or not), sometimes it just sounds weird to just tack on a suffix to make a new word that may or may not be a direct relation.

I say, with this new root word system, I could still say the word is derived from the root word, but perhaps there could be an infix (maybe even make it a grammatical rule of some kind?). It wouldn't be a crazy concept. English does tons of weird things to words when parts of speech etc change ("goose" and "geese", for instance). English and most languages, in fact, also have irregular verbs and other words that don't follow the rules. "To be" in most languages is basically completely insane, being, arguably, the first word to ever be uttered by any human, and like all old words has its own set of rules.

Anyway, just my rambling thoughts. 

I can't think of any infixes in the canon language, but when using "-gaar" to form adverbs I tend to use infixes a lot.  For example, "Valk" is "nervous", so literally "nervously" would be "Valkgaar", but I made it into "Valkagaar" to give it a more natural pronunciation.  Another example would be "Zopaar", "ambition".  Literally it would be "Zopaargaar", but I made it "Zopagaar".

Another way to get around this is, if you know your word is going to use "-dahk"/"-ak"/whatever the heck we decide it to be, try to avoid having it end in a way that would make that suffix difficult to use ("Suhak" vs. "Sukah").

Well, all lenguages are strange in its way, like "Hey guys, here a new grammatical rule, and here you have 573 exceptions"

The verb to be in portuguese is SO STUPID there are NO RULES, and it has a different conjugation to each pronoun, and we have perfect tense, a continuos one, two different pasts, and a future, only the simple ones, there are the complexes, those are terrible, we have to use the verb "to have" ("ter") with what we call "participio passado" that is "been" ("sido") and we confugate "to have" in each pronoun, using its past tense to create the complex present, and a lot of things like that is terrible

This is perfect tense in portuguese with the english translation:

Eu sou (I am)

Tu és (You are)

Ele/Ela é (He/She/It is)

Nós somos(We are)

Vós sois(Plural of you are, something like you all are)

Eles são(They are)

And there are two pasts, we have "Pretérito perfeito", literaly "perfect past", to mean something we have done and its done nothing more, like "i did". The other one is "Pretérito mais-que-perfeito", literaly "More-then-perfect past". It is used on a phrase like this: "I did this, but before that i did that". That second "did", would have a different confugation (Pretérito mais-que-perfeito) because is something you did before another thing that is talked about in the same phrase. In portuguese, the first did would be "fiz" while the second one would be "fizera". Eu fiz aquilo, mas antes disso ei fizera aqueloutro" (another interessing thing, the dovahzul lenguage usualy combine 2 words togeder to make new words. The word "aqueloutro" is said the same way you would say "aquele outro", its a combination, because on cummon speach it was a cummon thing to say, "aquele outro", that later become one other word "aquele outro" literaly would be "That other", or "That other one")