I'm not really sure what you mean by Italic languages there. By the Vth century, it's quite unlikely that any other Italic language known in Antiquity (among them Oscan, Liburnian, Sabellic, Siculian, etc.) than Latin survived.

Maybe you meant Romance languages, that came from Vulgar Latin and which include Italian, French, Spanish, etc. which didn't emerged as such before the VIIIth at earliest for Old French. In the VIth, virtually all of western Romania was linguistically dominated by Vulgar Latin, not just the part ruled by Ostrogoths and Wisigoths, but also in Gaul (Gallo-Romance), Spain ruled by Suevi (Hispano-Romance), Africa ruled by Vandals and then Byzantines (Afro-Romance) and various Balkano-Romance speeches.While Gallo-Romance and critically Retho-Romance speches have a quite important Germanic influence; they are unmistakeably Romance languages.

The early linguistic history of Rumanian is still debated, between a native continuity theory (Rumanian coming from a Daco-Roman presence since Trajan conquest in Carpathian-Pannonian basin) and migration theory (Rumanian originates from southern Balkano-Romance speeche which encompasses Arumanian, Istrio-Roman, Dalatian, etc.). Regardless, Gepid attested presence (trough litterary sources or graves) point they weren't systematically present where Rumanian language is attested.

Eventually, it's neither a pattern or a coincidence, as Romance languages presence is well attested outside and after Gothic kingdoms in western Europe.

Thank you for your pointers

I am basing my “Pattern” for the Balkans on this work https://www.academia.edu/38727041/Eastern_Europe_in_the_Middle_Ages_500-1300_ In short, the book describes the situation in the Balkans in very dramatic terms for the VI century. It refers to both written sources and archeological surveys of most known sites from that time in that region. It also sources from the same author's earlier book 'The making of the Slavs'

Briefly, due to over taxation and abuse the Eastern Roman Empire lost its civilian population of the Balkans. People choose to flee, and had abandoned their lands and cities on a very large scale for the reason of a tax law making one responsible for paying taxes due by any neighbor who have fled (btw. the law stayed in effect until the mid XI century). During Justinian’s time the area South of Danube became a true military zone but lacked any civilian settlements (such as farms). Lots of new fortifications were erected, all manned with mercenaries and fed with shipments from as far as Egypt.

The mass migration (refuges) of Latin speakers from the South did happened during that time for sure. They must have fled to the Gepidic Kingdom which was centered in what is now known as Transylvania. The problem is that the Northern frontier of the Eastern Roman Empire collapsed when Phocas with the rest of the army usurped the Emperor Maurice in the late VI century. At that time a mass of Slavic tribes pored in and occupied the entire peninsula without much fight as there was almost nobody to oppose them. The Byzantines never recovered the area for another 4 centuries

Starting the early VII century, there are only sporadic written sources about Romanians (or Dacia). Also the flux of Byzantine currency stopped shortly after making it difficult to date any archeological finding in the area after the reign of Heraclius. Until the middle of XII century the area is not mentioned as a territory by itself but shortly after it was coined as Transylvania (the land beyond the forests)

I wanted to check if the above seems reasonable as a theory (we cannot rewind time to actually verify the facts on the field). If so, it maybe that the Goths did help with the preservation and evolution of the vulgar Latin indeed