Bi- and multilingualism is not a new phenomenon, it has always been present throughout history in most kingdoms, monarchies and countries as people learned other languages for several reasons (e. g. to merchandise). However, systematic research has not started until the mid 20th century which later accelerated and resulted in the proliferation of monographs, journals, articles and blogs in the beginning of the 21st century onwards. One of the main findings that has been well documented is the bilingual advantage, i. e. bilinguals outperform monolinguals on nonverbal tasks, which require language-independent conflict resolution or switching between tasks. (Bialystok–Martin, 2004) However, on language-related tasks, they perform worse compared to monolinguals: they are slower on picture naming tests (e. g., Gollan et al., 2005; Ivanova–Costa, 2008), on translation-recognition tasks (e. g., Sunderman–Kroll, 2006; Talamas et al., 1999) and in lexical retrieval (e. g., Gollan et al., 2005), bilinguals experience more tip-of-the-tongue states (e. g. Kreiner–Degani, 2015; Stasenko–Gollan, 2019) and have a smaller vocabulary in each of their languages (e. g., Oller et al., 2007). Most of these findings can be explained by the cross-linguistic influence (CLI) between the two languages. Experimental research has repeatedly found that the bilingual’s two languages are always active and interact.