This study relies on the constrained communication framework to compare the use of embedded inversion in English
as a Foreign Language (EFL) and English as a Second Language (ESL). It is based on several (sub)corpora of EFL and ESL, but also
reference corpora of native English, which differ along the constraint dimensions of language activation (monolingual/bilingual),
proficiency (native users/proficient L2 users/learners), and modality (speech/writing). In addition to these constraint
dimensions, we also investigate the possible effect of linguistic factors that have been claimed to play a role in the use of
embedded inversion. A multifactorial analysis comparing embedded inversion with standard-like indirect questions, supplemented by
a close examination of the patterns of use of embedded inversion, reveals both shared and distinctive features across EFL and ESL.
It also highlights the importance of linguistic factors and variety/L1, and their interaction with communicative constraints.