Ah, the infamous capitalization of Nouns in German (see http://german.about.com/library/weekly/aa020919a.htm)
You could try a list comprehension and lower each token from the swadesh corpus:
>>> from nltk.corpus import swadesh
>>> de2en = [(i.lower(),j.lower()) for i,j in swadesh.entries(['de','en'])]
>>> translate = dict(de2en)
>>> translate['hund']
u'dog'
>>> translate['Hund']
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
KeyError: 'Hund'
But you would have lost the capitalization in the key. So to resolve that you can update the translate
dictionary again with the original swadesh entries:
>>> from nltk.corpus import swadesh
>>> de2en = [(i.lower(),j.lower()) for i,j in swadesh.entries(['de','en'])]
>>> translate = dict(de2en)
>>> translate.update(swadesh.entries(['de','en']))
>>> translate['hund']
u'dog'
>>> translate['Hund']
u'dog'