Non Arabic Proper nouns:
Most of the non Arabic proper nouns are unnunated and therefore they do
not take Tanwin. e.g.,
The Biblical Names: Most of the
Biblical names do not take Tanwin e.g., names of most of the prophets:
i.e., يَعْقُوْبُ،
اِسْحَاقُ،
عِيْسَى،
دَاوُدُ
etc.