This is the 9234th most frequent Turkish word.
volker
The word "volker" is not Turkish. It may be a German name meaning "people's guard" or have another origin.
In this sentence, 'Volker' is used as a proper noun referring to a person's name.
Volker sabah erken kalktı.
Volker woke up early in the morning.
Here, 'Volker' is again used as a proper noun, emphasizing a specific person to contact regarding a job.
Yeni iş için Volker ile iletişime geçmelisin.
You should contact Volker for the new job.
In this example, 'Volker' refers to an individual's opinion which holds importance for making decisions, thus used as a proper noun.