There are several critical differences between Turkish coffee and regular coffee:

Grind size: Turkish coffee is made using finely ground coffee beans, while regular coffee is made using beans with a coarser consistency.

Preparation method: Turkish coffee is traditionally prepared using a small pot called a cezve or ibrik, which is heated over a stove or open flame. 

The finely ground coffee is mixed with cold water and sugar (if desired) and placed in the cezve. The mixture is brought to a boil and removed from the heat just before it boils. Regular coffee is prepared using a coffee maker or pouring hot water over ground coffee in a filter.

Serving method: Turkish coffee is traditionally served in small cups, often with the grounds still present. The grounds settle to the bottom of the cup as the coffee is consumed. Regular coffee is served in a mug or cup and filtered to remove the ground.

Flavour and texture: Turkish coffee is known for its robust, rich flavour and thick, creamy texture. Regular coffee can have a wide range of tastes and textures depending on the type of beans and brewing method used.

Turkish and regular coffee are both types of coffee but differ in their preparation, serving, and flavour characteristics.