id	keyword
edu-5488	language
edu-5488	learning
edu-5488	duolingo
edu-5488	language learning
edu-5488	speaking
edu-5488	proficiency
edu-5488	study
edu-5488	education
edu-5488	group
edu-5488	research
edu-5488	test
edu-5488	journal
edu-5488	control
edu-5488	learners
edu-5488	skills
edu-5488	language proficiency
edu-5488	acquisition