This greeting (GROET) shows how fond English and Dutch are of each other. In fact they love each other. In their long relationship they have shared words and exchanged them.
HALLO was given to the Dutch in the nineteenth century. This interjection was probably communicated and made popular by the earliest telephones in the 1890’s. ‘Hallo, wie is daar?’( Hello, who’s there?) ‘Hallo, met wie spreek ik?’ (Hello, who am I speaking to?)
This English word probably goes back to Middle French holà (literally: ‘hi there’) or to German ‘holà’ (imperative of ‘holen’, Dutch ‘halen’) as a call for the ferryman: ‘Hallo, hallo, ferryman, come and get me!’ VEERMAN, KOM ME HALEN!
Since 2005 there has been a famous airport reality show on Dutch television called ‘Hello, Goodbye’. Joris Linssen is the host. This format was sold all over the world. Russia had three seasons. On Sky 1 it was hosted by Kate Thornton in 2009.
HALLO often means ‘dag’. It is an informal greeting as in: ‘Hallo, hoe gaat het?’ However, as Louis pointed out in his comment, it can also be a cry of surprise or indignation, as in: ‘Hallo, wat krijgen we nu?’ When I cycled to the city centre to buy bread this afternoon, I saw gulls, geese and ducks fighting over some pieces of bread. A defeated duck seemed to say to the geese: ‘Hallo, mag ik ook een stukje brood!’ (Hello, can I have a piece of bread too!). This brutal street scene demonstrated once again that nature is all but democratic.