to hear something through the grapevine, to hear informally
[Dutch phrase of the week] 

"Wandelgang" is composed of "wandel" and "gang", which respectively translate to "walk/stroll" and "hallway/corridor". As an expression, "iets in de wandelgangen horen" is used in a situation where information is informally acquired.

Examples:
– "Ik hoorde in de wandelgangen dat je niet veel langer de mijne zou zijn…" 
("I heard it through the grapevine, not much longer you would be mine…")

– "Ik hoorde in de wandelgangen dat Frank zijn baan zal verliezen." 
("I heard it through the grapevine that Frank will lose his job.")

– "Ik heb veel gelobbyd via mijn informele netwerken, nu hoor ik in de wandelgangen dat mijn advies door het management zal worden gevolgd." 
("I've lobbied a great deal via my informal networks, now I hear it through the grapevine that my advice will be followed by the management.")

Expressions:
– "Tussen neus en lippen door": informally.

Example:
– "Ik begreep tussen neus en lippen door dat Daniel achterdochtig had gereageerd. Klopt dat?"
("I understood informally that Daniel had reacted with suspicion. Is that right?")

– "Tussen de regels door": between the lines.
– "Van horen zeggen": hear say.

Related words:
– Gang: hallway, corridor [noun] [de gang, de gangen].
– Gerucht: rumour [noun] [het gerucht, de geruchten].

Example:
– "Het gerucht doet de ronde dat…"
("Rumour has it that…")

– Wandelen: to walk, to stroll [verb] [wandelen, wandelde, h. gewandeld].