"Everyone listens while the man speaks to his wife."
Translation:Iedereen luistert terwijl de man met zijn vrouw spreekt.
The translation seems to mean "Everyone listens while the man speaks with his wife." This has a different meaning in English than "Everyone listens while the man speaks to his wife." The former is a conversation, the latter perhaps instructing or scolding her. How can the different meanings be differentiated?
Speaking with would be praten met, speaking to would be praten tegen. So you are right the translation is off
"Spreekt met zijn vrouw" should be permissible, no? Since prepositional phrases can go after the final verb.