History of linguistics (20th century) ; History of linguistics (21st century) ; UG; Universal grammar ; Learnability (of language) ; Lernbarkeit (von Sprache) ; Spracherwerb (Theorie) ; Language acquisition (theory of) ; Poverty of the stimulus-argument; Theory (language acquisition) ; Interimsgrammatik (Spracherwerb) ; Lernervarietät (Spracherwerb) ; Learner variety (language acquisition) ; Interlanguage (language acquisition) ; Transfer (second language acquisition) ; Transfer (Zweitspracherwerb) ; Cross-linguistic influence (second language acquisition) ; Interference (second language acquisition) ; Triggering (second language acquisition) ; Parametrization (second language acquisition) ; Critical period (second language acquisition) ; Alter (Einfluss auf Zweitspracherwerb) ; Age (influence on second language acquisition) ; Ultimate attainment (second language acquisition) ; Near-native competence (second language acquisition) ; AoA; Age of acquisition (second language acquisition) ; Sensitive period (second language acquisition)