Learn Farsi: کل شهر رو به دگرگونی است. - The whole city is heading towards transformation.

The phrase رو به literally means "face to" or "facing." When combined with an abstract noun like دگرگونی (transformation) and a copula verb like است (is), it describes an ongoing trend or trajectory. It expresses that the city is currently on the path of transformation, rather than just a simple action happening right now.

How is the abstract noun دگرگونی formed?

It comes from the adjective دگرگون (altered, changed, or transformed). By adding the suffix ی, which forms abstract nouns from adjectives (similar to "-ness" or "-tion" in English), we get دگرگونی (transformation).

Why use کل شهر instead of همه‌ی شهر for "the whole city"?

Both mean "the whole city" and are often interchangeable. However, کل is an Arabic loanword meaning "the entirety of," making کل شهر slightly more formal and emphatic about the city as a single, unbroken unit. Remember that both require the ezafe vowel to connect to the following noun.

Since the English translation says "heading," could we use a verb of motion instead of the "is" verb است?

Yes, you could say رو به دگرگونی می‌رود (is going towards transformation), which emphasizes the action of moving toward change. However, using the "to be" verb است with رو به is a very standard way to describe the current state of a trend. It simply means the city's current condition is defined by being on this trajectory.