AUTHOR=Thomson Ron I. 

TITLE=Commentary: When the Easy Becomes Difficult: Factors Affecting the Acquisition of the English /iː/-/ɪ/ Contrast and On the Difficulty of Defining “Difficult” in Second-Language Vowel Acquisition

JOURNAL=Frontiers in Communication

VOLUME=6

YEAR=2021

URL=https://www.frontiersin.org/journals/communication/articles/10.3389/fcomm.2021.748991

DOI=10.3389/fcomm.2021.748991

ISSN=2297-900X