Sefyll arholiad
Some phrases cannot be literally translated into Welsh.
In Welsh, we do not literally translate 'to sit an exam' to eistedd arholiad. Instead, we use sefyll arholiad which, if literally translated to English, means 'to stand an exam'!
Another example is to 'play an instrument'. In Welsh, we do not use chwarae in this context. Instead, we use canu (to sing), e.g.
Mae Alun yn hoffi canu'r piano.