What is the difference between "J'ai faim" and "Je suis faim?" By looking at different sources, I found out that most people say "J'ai faim," although I wanted to know if there was anything wrong with using the latter.

"J'ai faim" is the proper expression to say "I am hungry."

Just like in English we would not say "I am hunger", it would be incorrect say the equivalent in French.

Another notable difference in French from English is about age.
We would say "J'ai quinze ans" to mean I am fifteen. The verb "ĂȘtre" is not correct for this usage.

The phrase "J'ai faim" means "I am hungry" in French, whereas "Je suis faim" does not have a correct translation.

To understand the difference, it's useful to know that the verb "avoir" means "to have" in French, and it is used to express states or sensations. In this case, "j'ai" is the first-person singular form of "avoir" (I have), and "faim" means "hunger." So, "J'ai faim" literally translates to "I have hunger."

On the other hand, the phrase "Je suis faim" is incorrect because "faim" is considered a noun in French, and nouns cannot be used directly after the verb "ĂȘtre" (to be) to express a sensation or state. Instead, French uses the construction "avoir + noun" to denote hunger, thirst, or other sensations.

While you may find variations in language usage among different sources or native speakers, "J'ai faim" is the standard and widely accepted way to express hunger in French. Using "Je suis faim" might sound odd or incorrect to native speakers.

If you are uncertain about the correctness of a phrase in French, it's recommended to consult reputable language resources or native speakers for clarification.