the apparent flexibility of English in informal or semi-formal contexts, which may sometimes lead learners to omit subjects under the assumption that such omissions are tolerated across a range of communicative situations, even though standard English structures typically require explicit subjects. 

learners’ inclination toward brevity and simplified sentence structures, which reflects a general strategy to minimize cognitive load during second language production, rather than stemming from syntactic patterns of their native language.

first language transfer from Portuguese, where subjects can frequently be inferred from verb conjugation, resulting in learners producing English sentences without explicit subjects despite the grammatical necessity of including them in standard constructions. 

learners’ deliberate attempt to omit subjects as a stylistic or creative choice, under the mistaken belief that leaving out the subject enhances the expressive or rhetorical quality of the sentence.

perceived ambiguities in English grammar that learners interpret as allowing optional subject omission, leading to a variety of sentence constructions that do not conform to the conventional syntactic rules of standard English.