Crosslinguistic influence (CLI) refers to the different ways in which one language can affect another within an individual speaker.
CLI can be observed across subsystems of languages including pragmatics, semantics, syntax, morphology, phonology, phonetics, and orthography.
It was based on evidence of monolinguals and bilinguals reaching the same milestones at approximately the same stage of development.
[8] In response to both the previous hypotheses mentioned, the Interdependent Development Hypothesis emerged with the idea that there is some sort of interaction between the two language systems in acquisition.
It re-examined the extent of the differentiation of the language systems due to the interaction in difficult areas of bilingual acquisition.
[9][10] Evidence for this hypothesis comes from delay, acceleration, and transfer in particular areas of bilingual language acquisition.
In the Applied Linguistics field, it is also known as exhibiting knowledge of a native or dominant language (L1) in one that is being learned (L2).
Because the languages are so similar, the speaker could rely on their knowledge of Spanish when learning certain Catalan grammatical features and pronunciation.
However, the two languages are distinct enough that the speaker's knowledge of Spanish could potentially interfere with learning Catalan properly.
[19] Underproduction as explained by Schachter (1974),[20] is a strategy used by L2 learners to avoid producing errors when using structures, sounds, or words which they are not confident about in the L2.
[21] Overproduction refers to an L2 learner producing certain structures within the L2 with a higher frequency than native speakers of that language.
French learners have been shown to over-rely on presentational structures when introducing new referents into discourse, in their L2 Italian[23] and English.
[24] This phenomenon has been observed even in the case of a target language where the presentational structure does not involve a relative pronoun, as Mandarin Chinese.
[30] Argyri and Sorace (2007) found, much like many other researchers, that language dominance plays a role in the directionality of CLI.
Take for example the fact that most L2 learners are receiving input or teachings from similarly speaking bilinguals; Hauser-Grüdl, Guerra, Witzmann, Leray, and Müller (2010) believe that the language being taught has already been influenced by the other in the teachers' minds and, therefore, the input the learner is receiving will exhibit influence.
Other researchers believe that CLI is more than production influences, claiming that this linguistic exchange can impact other factors of a learner's identity.
Jarvis and Pavlenko (2008) described such affected areas as experiences, knowledge, cognition, development, attention and language use, to name a few, as being major centers for change because of CLI.
[33] CLI has been heavily studied by scholars, but there is still much more research needed because of the multitude of components that make up the phenomenon.
Also, research is needed in specific areas of overlap between particular language pairings and the domains that influence and discourage CLI.
More generally, an area of research to be further developed are the effects of CLI in multilingual acquisition of three or more languages.
[34] Gaston, P. (2013)Syntactic error processing in bilingualism: an analysis of the Optional Infinitive stage in child language acquisition (Unpublished doctoral dissertation).