The verb to be can be translated as "ser" or "estar" in Spanish and both mean different things. I was trying to look for a way to explain this difference from the point of view of an English speaker and it was quite hard since this comes naturally to me.
You can use "ser" to describe a thing (example: La casa es grande / The house is big), a person (example: Ella no es mi hermana / She is not my sister) or yourself (example: Yo soy una mujer / I am a woman). To describe a permanent mood (example: Soy feliz / I am happy).
You can use "estar" to describe a temporal mood (example: Estoy triste / I am sad), a sickness (example: Yo estoy enferma / I am sick) or the location of something or someone (example: El está en la casa / He is at the house). You can also use it to describe an action that is happening right at the moment as you are speaking or writing (example: Yo estoy comiendo / I am eating), it is usual to see the verb to be "estar" next to another verb in this cases.
I've studied the verb to be as “ser” in my target languages, I've not looked if this differences exist in German and Italian for the verb “estar”. I think that Italian will have a verb “estar” since Spanish and Italian are both romance languages, but will German do? English and German are both Germanic languages so there is a chance I won't find a verb “estar”. I took a break from verbs so I'll study this later.
Have you found a peculiar difference in the languages you are learning? Differences that could change the way you think.