Koǹsonanti aìkuǹyùn afeyìnfètèpè afunnupè ni

A voiceless consonant is made without vocal cord vibration. The sound [f] is voiceless. Air passes through without your throat buzzing.

It is also made between bottom lip and top teeth (labiodental). And air flows out continuously (fricative). These three features together identify [f].

The other sounds have different features. [b] and [d] are voiced. [g] uses the back of the mouth. Only [f] has all three qualities.