One of the common phenomena and misconceptions is the"infantilization of adult non-native language users" (there must be a linguistic jargon for this term, linguists or people versed in this field, help me!), and this tendency is much more pronounced in novice-level users.
The possible reason for this misconception has two layers.
Non-native language users' speech patterns/utterances (short & choppy or word-chunk-like utterances; "Mom food love", "you no college", "Rocky new to ball") resemble first-stage speech patterns, occurring at a very early age, in infancy.
People generally associate language proficiency with their cognitive ability. Language is a powerful medium, which is used permanently once acquired & with much repetition, that can directly convey one's thoughts. Aligning with the said notion, people show great appreciation & respect to the people who have a way with words.
Misinterpretation occurs when putting these two together:
An adult non-native person's cognitive ability is equal to their current (non-1st) language level.
This misconception is prevalently & frequently consumed as jokes on sitcoms, especially as a hallmark joke for non-native characters.
(Character having an exaggerated accent with wonky pronunciation & wrong intonation. Mistook similar words or a certain word in phrases, and it happens all the time. The other character tries to rectify his phrase "No, it's~ not ~, (character's name). (*THAT DREADED LAUGH TRACK ENSUES*) At this point, you can probably hear the recorded laugh tracks any time that character utters a single word with their distinctive speech repertoire.)
Gloria Delgado-Pritchett (from "Modern Family") once shouted out with genuine frustration about being laughed at by others for her English.
Cha Eugene (from "Debut or Die" ("데뷔 못하면 죽는 병 걸림")), also a multilingual character (whose first language is English) and became an idol in Korea.
At first, the main character (MC) from the same group misconstrues Eugene as juvenile (not only that, BUT also his peppy, energetic personality & being the youngest member of the team heightened this notion). However, as they know each other more, MC realizes that Eugene is a very considerate & much more mature person, and he was blinded by the language. There are moments of this realization depicted in the novel, here and there.
It is difficult NOT to learn this misconception in the first place (due to our environment & this largely has to do with our basic perception regarding language itself). However, we can at least acknowledge this phenomenon & can try NOT to follow judgments based on this misconception.
