It seems that there are quite a few terms that look like English and are used in English spoken by non-fluent or fluent but nonnative speakers of English as a second language amongst themselves, but not by, or only very rarely by, native English speakers.
Here's a few that spring to mind before I look for a resource:
Also I know there is an English Wikipedia article on this phenomenon in which the preferred term is "Pseudo-anglicism". You'll find a lot more such terms there. Not only "incorrect" regular plurals of words that have no separate plural form that I was able to think up without peeking.
The most surprising thing for me was that many of these words and strange plural forms have English entries in the English edition of Wiktionary - mostly without any kind of note suggesting they are anything other than normal everyday words any English speaker might make!
I'm interested in both prescriptivist and descriptivist view on this topic. I'm also interested in both English native speakers view and non-native speakers.