In Greek, whispering is a verb from the same stem as the noun used in verse 12.
Certain subtle complications are involved in rendering the clause The Pharisees heard the crowd whispering these things about Jesus. First of all, the phrase the Pharisees might be assumed to mean “all the Pharisees.” Since this was clearly not the case, it may be necessary in certain receptor languages to employ an expression meaning “some Pharisees.” It is also important to use a term for heard which means “overheard,” in order not to give the impression that the crowd was whispering so loudly that the Pharisees could not help but hear. It may be necessary as well to say “people in the crowd were whispering,” since in some languages one cannot speak of “a crowd whispering.”
They and the chief priests is literally “the chief priests and the Pharisees.” Good News Translation restructures this phrase because the Pharisees are already mentioned in the first part of the verse. Most of the chief priests were Sadducees, and it was unusual to find them acting together with the Pharisees. But in John’s Gospel the two groups appear together often (7.32,45; 11,47,57; and 18.3). John more often uses the term “the Jews” (Good News Translation generally the Jewish authorities) to describe the enemies of Jesus, but occasionally he refers to them as “the chief priests and the Pharisees,” or “the authorities and the Pharisees.”
As already noted, the word translated guards is best understood as a reference to “Temple police” (so New English Bible and several others). In 18.3 and 19.6 Good News Translation translates the word temple guards, but elsewhere as guards (7.45,46; 18.18,22) or Jewish guards (18.12), except at 18.36, where it has a different meaning (Good News Translation my followers). The persons referred to were certainly not Romans but Jews, perhaps Levites, and they were under the authority of the chief priests.
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 .