Exegesis:

humnēsantes (only here in Mark) ‘having sung a hymn’: at the end of the Jewish Passover, Psalms 115-18 were sung.

to oros tōn elaiōn (cf. 11.1) ‘the Mount of Olives.’

Translation:

Hymn has been translated as ‘prayer song’ in Barrow Eskimo. In other languages it is rendered as ‘song of praise’ or ‘singing of thanks.’

For Mount of Olives see 11.1.

Quoted with permission from Bratcher, Robert G. and Nida, Eugene A. A Handbook on the Gospel of Mark. (UBS Handbook Series). New York: UBS, 1961. For this and other handbooks for translators see here .