This study investigates the acquisition of sociophonetic competence by English as a foreign language learners in production and perception. Adult learners of English completed speaking, listening, and questionnaire tasks, aimed at assessing their acquisition of sociolinguistic constraints on (ING). First, they were interviewed and read 30 sentences, containing the target variable, in English. Next, they participated in a listening task where they had to discriminate between more and less formal sentences, varying in the (ING) variant. Lastly, they completed an awareness and biographical questionnaire. An analysis of the speaking task revealed partial acquisition of variable rules: The alveolar variant was more likely to appear in verbs and the velar one—after an alveolar consonant. Style was not significant. Participants also did not distinguish between velar and alveolar variants in perception of formality. Measures of English proficiency and exposure did not predict acquisition of (ING) in production and perception. The questionnaire revealed minimal awareness of (ING) and other phonetic/phonological variables, which may be one of the contributing factors to its incomplete acquisition in production and perception.