I personally would expect that the /T/ and /D/ would merge with /t/ and /d/. And since few Native languages in that area have voiced-voiceless contrast I would expect it to become an aspirated-nonaspirated or a lenis-fortis distinction. And I would expect the front rounded vowels to go away (in other words break up or unround) since I don't think any of the native languages in that region have them. And why are you going analytic on us?!?!?! I want to see more synthesis.

I suck at phonology. >.<

/t/ and /T/ have merged, and /D/ was always an allophone of /d/. The correct IPA was /ð̞/ anyway.

Voicing contrast is being phased out, usually voiceless stops are at the end of a word or in a cluster with other voiceless stops, and voiced stops are intervocalic and in clusters with sonorants, basically how the voicing contrast works in Míkmaq.

I've been think think that the front rounded vowels should be gotten rid of too, none of the languages spoken around there have those sounds, and my phonology has already been changed a bit for the languages around there.

I'm going analytic, because this is supposed to develop similar to English (Old English was in contact with Old Welsh, and Old Norse, but began to become more analytic to bridge the gap between languages.)

Isn't that usually what happens when you have two languages with totally different grammars? I have it planned that Sklang will have a creole, called Sjeiling (Named after the skrælingar ) that most people speak something in between Sklang and Sjeiling, kind of like the situation Patois and English in Jamaica, some people speak English, and some Patois, but most speak something in between the two.

No that only happens in the case of pidgins and creoles. I would expect that since there would be a large populations of native speakers that their grammatical influence would push it more into the synthetic zone. And English lost its declension and inflection thanks to fact they were unstressed and english maintained some of the verbal inflection (in the present tense) untill resently. So I would hardly say that it was trying to bridge the gap between Old welsh and Old norse. And since it would isolated from the other european languages for such a long time I highly doubt it would develop like the other european languages. And I would expect to have the creole be that of a native language instead of Sklang.

I know you want this to develop like English, but this kind of "expected answer" business is, in my humble opinion, a little too close to English. Having a negative answer particle is often asking for confusion, as exemplified by the song "Yes, we have no bananas". In Tikolmian, we use word order to indicate that we're sure of the answer one way or another. So if I asked "Fish don't fly?" in Tikolmian, the correct answer would be "Yes, they don't," not "No, they don't." (Incidentally, some of them do fly. They're called flying fish. I'm also being a know-it-all by saying this.) Not that you should care about my (here) totally irrelevant language -- it's just an example of another option. In any case, feel free to ignore everything I just said.
This sentence doesn't demonstrate aisut.
I like this.