the first language which is normally acquired by a human being in early childhood through interaction with other members of his speech community, language variety(ies) acquired in early childhood (approximately before the age of two or three years) in which the human language faculty was first acquired, keel, mille inimene lapsena emalt (vanemailt) omandab ning mida ta hrl. kõige täielikumalt oskab, esimese keelena kõige varasemas lapsepõlves vanemailt v. kasvatajailt omandatud keel, mida inimene hrl. kõige paremini oskab