Я подозревал, что Убервальд - это неспроста, но, конечно, не мог ничего знать, пока случайно не наткнулся на статью о https://en.wikipedia.org/wiki/Transylvanian_Saxons:
The initial phase of German settlement began in the expansive mid-12th century, with colonists travelling to what would become Altland or Hermannstadt Provinz, based around the city of Hermannstadt, today's Sibiu. Although the primary reason for Géza II's invitation was border defense, similar to employing the Székelys against invaders, Germans were also sought for their mining expertise and ability to develop the region's economy. Most colonists to this area came from Luxembourg and the Moselle River region (see for instance Medardus de Nympz).
A second phase of German settlement during the early 13th century consisted of settlers primarily from the Rhineland, the southern Low Countries, and the Moselle region, with others from Thuringia, Bavaria, and even from France. A settlement in northeastern Transylvania was centered on the town of Nösen, the later Bistritz (Bistrița), located on the Bistrița River. The surrounding area became known as the Nösnerland.
Continued immigration from the Empire expanded the area of the Saxons further to the east. Settlers from the Hermannstadt region spread into the Hârtibaciu River valley (Harbachtal) and to the foot of the Cibin (German: Zibin) and Sebeș (German: Mühlbacher) mountains.
The latter region, centered around the city of Mühlbach (Sebeș), was known as Unterwald.
Вот чем объясняется немецкий акцент у Дорины Мигль, графини фон Бурдалак.