Many region names (and some place names) in Europe derive from the original Germanic word for stranger or foreigner, rendered as "wal" or "gal" (and variations). In the original Germanic languages, the letters w and g were quite interchangeable. (For instance, the Germanic Normans said 'guardian', 'guerre' and 'guiliam' whereas the Anglo-Saxons used 'warden', 'war' and 'william').
"Gal/Wal" especially came to mean "strangers at the edge of (our) region". Examples of place/region names deriving this way include:-