In all of these references, the gerah only appears as a definition of the shekel, of which it is 1/20; that is, the gerah has no significance apart from the shekel. If the name “shekel” is retained in translation, then the name “gerah” may also be kept. If the word “shekel” is translated, it may still be possible to retain the word “gerah,” because you will just be saying it is 1/20 of the unit used for “shekel.”