Exegesis:

erōtēsō humas kagō logon ‘I too will ask you a question.’ For logos meaning ‘question.’

kai eipate moi ‘and tell me’; kai is semantically redundant. The imperative calls for an answer to the direct question of v. 4.

(V. 4) to baptisma Iōannou ex ouranou ēn ē ex anthrōpōn ‘was the baptism of (i.e. preached and administered by) John from heaven or from men (i.e. of divine or human origin, due to divine or human initiative)?’

Translation:

Since Jesus replied with another question a literal rendering of he answered them is sometimes unacceptable; hence, ‘he spoke to them again’ (Navajo).

I also will ask you a question, or, ‘now let me ask you a question’ (cf. Good News Translation). The combination ‘ask a question’ is too redundant in some languages; hence, ‘I too will ask you something’ (cf. Sranan Tongo, Javanese, Toraja-Sa’dan).

(V. 4) Was the baptism of John from heaven or from men, or, “did John’s right to baptize come from God or from man” (Good News Translation), ‘when John baptized, was his power from heaven or from man’ (Kekchi), ‘the baptism of John, (was) its origin from heaven or from man’ (some Indonesian languages), ‘who caused/sent/told John to baptize (people), God (in heaven) or men?’ For baptism see on 3.3.

Quoted with permission from Reiling, J. and Swellengrebel, J.L. A Handbook on the Gospel of Luke. (UBS Handbook Series). New York: UBS, 1971. For this and other handbooks for translators see here . Make sure to also consult the Handbook on the Gospel of Mark for parallel or similar verses.