This is the 9783rd most frequent Russian word.
эстонский
Estonian.
In this sentence, 'эстонский' is used as an adjective to describe the noun 'язык,' denoting the Estonian language.
Я изучаю эстонский язык.
I am learning the Estonian language.
Here, 'эстонский' functions as an adjective modifying the noun 'костюм,' indicating the origin or cultural association of the costume.
Она носит эстонский костюм на праздник.
She wears an Estonian costume for the celebration.
In this instance, 'эстонский' acts as an adjective describing the noun 'народ,' referring to the people of Estonia.