Gothic is the only language in the East Germanic group of which any substantial trace remains. The main source is the Bible of Ufilas (fourth century). Gothic has many archaic features but it differs from the reconstructed Common Germanic.
As Ostrogothic it was established briefly in southern Italy, along the Danube and more securely in the Crimea. There is some evidence that a debased form was being used in the Crimea in the 16th Century.
It was spoken as Visigothic at various times in Aquitaine, and the Iberian peninsula (where it may just have survived until the Arab conquest).