In American English a period ( . ) is used as a decimal separator, but there are other places in the world where a comma ( , ) is used.
I would read a quantity of 7.5 as “seven point five” written as-is. But if you use a pause and not a point how do you read the number aloud?
In polish you can say: seven comma five, seven and a half, or seven and five tenths, or if you need more precision (for 7,55 for example) there is seven and fifty five hundredths and so on.