The clause where he had turned the water into wine may cause difficulty in some languages because it reflects an activity prior to the time of the verb in the main clause. Since this clause is primarily explanatory or identificational, it may be translated as a parenthetical statement in some languages, for example, “(That is where Jesus earlier turned the water into wine)” or “(… caused the water to become wine).”
The word Good News Translation here translates government official is rendered in other translations in various ways. Revised Standard Version and Phillips render “an official”; Moffatt and New American Bible “a royal official”; Jerusalem Bible “a court official”; New English Bible “an officer in the royal service.” The word itself may denote either a person of royal blood or one in the service of a king. Most translations take it in the latter sense, which appears to be the meaning intended here. The man may have been a Gentile, and possibly a soldier, though doubtless there were many kinds of administrative officials in Capernaum. However, what is important for John is the fact that he is from Galilee, as opposed to Judea (or Jerusalem), the center of hostility against Jesus. Since Good News Translation identifies this person as a government official in the present verse, when the word is used again in verse 49, it is simply translated as the official.
In this account John uses three different Greek words to describe the son, and Good News Translation attempts to maintain the distinction between them in translation: son (huios, verses 46,47,50), child (paidion, verse 49), and boy (pais, verse 51). In other contexts the last word (pais) may mean “servant,” but here the meaning of boy is evidently intended.
Some receptor languages may present problems because of the locations in verses 46 and 47. The spatial adverb there can be misleading, since it may suggest that the government official was already in Cana. However, the demonstrative there should refer to Galilee. As indicated clearly in 47, the official went to Cana, presumably from Capernaum.
Quoted with permission from Newman, Barclay M. and Nida, Eugene A. A Handbook on the Gospel of John. (UBS Handbook Series). New York: UBS, 1980. For this and other handbooks for translators see here .