Gothic language is preserved,in the Bible of Wulfilla and also there are some texts preserved,from Old Gutnish.
Old Gutnish is very closed to Old Norse,Gothic is East Germanic,the names are closed,but the languages were not really mutually intelligible.
Here a sample of Old Gutnish:
http://en.wikipedia.org/wiki/Old_Gutnish
There is a text preserved,from Old Gutnish:
en.wikipedia.org/wiki/Gutasaga
As for Gothic,is different.
http://en.wikipedia.org/wiki/Gothic_Bible
Getae were a Thraco-Dacian tribe so speakers of a Satem IE language,Geats were some kind of Norse people,so speakers of Old Gutnish,Goths were some East Germanic tribes,so speakers of East Germanic.
Speakers of Germanic languages are speakers of Centum languages,so what is the link with Thraco-Dacians?Only the fact that they were both Indo-Europeans.
As for that story of Jordanes,that tells that Goths came from South Sweden and are identical to Dacians,I do not think that part is actually true in that they were not identical to Dacians,not even by far.
Goths were allied with Dacians,but were not the same people.
Is possible that Goths might have started to migrate from South Sweden and as they were moving south their language shifted,becoming East Germanic,but how you can explain that I1 is not seen in the populations were Goths settled at so significant percentages?
Since in South Sweden most present paternal line is I1.
That Goths existed,that is clear,that they settled in Romania,Balkans,Italy,Spain that is also clear,but I doubt they were bearing mostly I1 on their paternal lines.So I doubt that they were actually Scandinavians.A thing that shows very clear the difference between them and Scandinavians is the fact they were not sea people,as Scandinavians were.
EDIT:
Yetos,you need more than a few resemblances of words to link two Germanic populations.
Now I remember another thing,look a little how Gothic leaders are named,Ala
ric,Ermena
ric,Teodo
ric etc see that most of their leaders are named with a ric at the name ending.
While Old Norse leaders are having different names,a very clear characteristic being that they have the name composed from 2 words,usually:
Haral
dr Hálfdanarson (known as Harald Fairhair) son of Halfda
nr Svarti or Íva
rr Ragnarsson (also known as Ivar the Boneless) etc.
Notice please,that the names of
Old Norse leaders are ending in
r preceded by another consonant,
not in ric,
as those of Gothic people.