How do you read the differential mark?
Formally, The derivative of...
Y equals the sine of f-of-x, implies that the derivative of y equals cos f-of-x times the derivative of f of x.
Informally, and depending on dialect, you can say either 'prime' (as per Humbulani's answer) or 'dash' - f prime of x, y-dash etc. The former is predominant in (but is not restricted to) the US, while the latter is relatively common in the wider Anglosphere.
Refer to: How do you pronounce the symbol ' in f'? and What is the practical difference between a differential and a derivative? for further information.
If x is a distance, ẋ can also be read as the x component of the velocity.
If x is a distance, and is also the only direction of motion, ẋ can also be read as speed or velocity.
If x is a distance, ẍ can also be read as the x component of the acceleration. If x is a distance, and is also the only direction of motion, ẍ can also be read as acceleration.
This mark means the first derivative of f. You can also call it a derivative of f. It is definitely wrong to call it the differential mark. American mathematicians read it as 'prime'. For example, f' (x) - f prime of x.
In high school and junior-high school in Japan, the symbol x' is usually pronounced as "x dash". However, in universities it is also read as "x prime". I think teachers in university are strongly influenced by Americans. I read it in both ways in a university.