There are a few languages, like Russian or Hebrew, which don't use copulas at predicative sentences.
What is a predicative sentence? It declares some predicament about something, like "The sun IS yellow" or "The sky IS blue" or "I AM Tarzan" or "You ARE Jane".
The verbs in caps don't indicate any real action, they only link the subject (sun, sky, Tarzan or Jane) with the predicament about them - that is why we call such verbs copulas.
Well, Russian, or Hebrew, or ape-men like Tarzan don't use copulas, they simply say "I - Tarzan. You - Jane".
One can think that is primitive, but this is how they do.
When translating a predicative sentence, if the final language DOES use copulas, you should use copulas. Otherwise your English will sound just as from an ape-man.