This paper investigates the perception of ‘being yourself’ when speaking in the second language (L2) in the context of mobility-migration. Participants consist of 149 highly educated sequential Polish-English bilinguals who relocated to the UK at the average age of 23, and underwent processes of acculturation. The independent variables in this study include acculturation level, social network profile, language of attachment in adulthood, language dominance, length of residence, predicted future domicile, gender, and age of L2 acquisition (AoA). The study employs both emic and etic approaches. The findings reveal strong links between the perception of being yourself in L2 and acculturation level, social network profile, language dominance, predicted future domicile, and language of attachment. The results show that sociocultural and psychological integration into the new society and culture are strongly linked to the perception of being yourself in L2. This study adds acculturation and attachment perspectives to current research on the perception of feeling different when using languages learnt later in life.