Exegesis:
toiautais parabolais pollais ‘with many parables such as these.’
toioutos (6.2; 7.13; 9.37; 10.14; 13.19) ‘such,’ ‘of this kind,’ ‘of this sort.’
elalei autois ‘he was speaking to them (all)’: autois ‘them’ includes the crowd (4.1) and the disciples; only to the disciples was the explanation given (cf. parallel Mt. 13.34).
kathōs ēdunanto akouein ‘as they were able to hear,’ ‘in proportion to their ability to hear’ (cf. Jn. 16.12, 1 Cor. 3.2).
chōris (only here in Mark) ‘apart from,’ ‘without.’
kat’ idian (6.31, 32; 7.33; 9.2, 28; 13.3) ‘privately,’ ‘alone.’
tois idiois mathētais ‘to his disciples’: although idios is properly ‘one’s own’ (as distinct from ‘another’s own’) it is often used simply as a synonym of the possessive pronoun ‘his’ – and that would appear to be its meaning in this passage.
epeluen (only here in Mark) ‘he interpreted,’ ‘he explained.’
Translation:
For parables see 3.23.
Spoke the word is the equivalent of ‘to preach,’ ‘to announce,’ or ‘to tell them the message.’ For preach see 1.4.
Because of the double reference in this verse, first to the people in general, identified as them, and later to the disciples, it may be necessary in some languages to translate as ‘Jesus told the good news to the people by means of many likeness-stories such as these.’ In Central Tarahumara this passage is rendered as ‘when he spoke … he only told them stories.’
As they were able to hear involves a rather complex type of proportion, rendered in Tzeltal as ‘as much as they could put in their hearts,’ in Inupiaqas ‘just as long as they could understand,’ and in Indonesian ‘according as they could understand.’
The double negative not … without must in some languages be rendered in a positive form: ‘he only spoke to them with parables.’
Privately is translatable as ‘when he was alone with his disciples.’
Explained everything maybe translated as ‘he told them what the stories meant.’
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 .