Yiddish: Walls have ears.

SOURCE: Bernstein, Jüdische Sprichwörter und Redensarten. Often followed by one of these:

Streets have eyes.  |  Gasn hobn oygn.  |  .גאַסן האָבן אויגן

SOURCE: Bernstein, Jüdische Sprichwörter und Redensarten

Streets have mouths.  |  Gasn hobn mayler.  |  .גאַסן האָבן מײַלער

SOURCE: Furman, Yidishe Shprikhverter un Rednsartn

‏‏ווענט האָבן אויערן.

Vent hobn oyern.

Walls have ears.