Language transfer
Language transfer is the application of linguistic features from one language to another by a bilingual or multilingual speaker. Language transfer may occur across both languages in the acquisition of a simultaneous bilingual, from a mature speaker's first language to a second or third language they are acquiring, or from an L2 back to the L1. Language transfer is most commonly discussed in the context of English language learning and teaching, but it can occur in any situation when someone does not have a native-level command of a language, as when translating into a second language. Language transfer is also a common topic in bilingual child language acquisition as it occurs frequently in bilingual children especially when one language is dominant.
Positive and negative transfer
When the relevant unit or structure of both languages is the same, linguistic interference can result in correct language production called positive transfer: here, the "correct" meaning is in line with most native speakers' notions of acceptability. An example is the use of cognates. However, language interference is most often discussed as a source of errors known as negative transfer, which occurs when speakers and writers transfer items and structures that are not the same in both languages.Within the theory of contrastive analysis, the systematic study of a pair of languages with a view to identifying their structural differences and similarities, the greater the differences between the two languages, the more negative transfer can be expected. For example, in English, a preposition is used before a day of the week: "I'm going to the beach on Friday." In Spanish, instead of a preposition the definite article is used: "Voy a la playa el viernes." Novice Spanish students who are native English-speakers may produce a transfer error and use a preposition when it is not necessary because of their reliance on English. According to Whitley, it is natural for students to make such errors based on how the English words are used. Another typical example of negative transfer concerns German students trying to learn English. Since the German noun "Information" can also be used in the plural – "Informationen" – German students will almost invariably use "informations" in English, too, which is grammatically wrong.
From a more general standpoint, Brown mentions "all new learning involves transfer based on previous learning". That could also explain why initial learning of L1 will impact the learning of L2.
The results of positive transfer go largely unnoticed and so are less often discussed. Nonetheless, such results can have a large effect. Generally speaking, the more similar the two languages are and the more the learner is aware of the relation between them, the more positive transfer will occur. For example, an Anglophone learner of German may correctly guess an item of German vocabulary from its English counterpart, but word order, connotations and collocation are more likely to differ. Such an approach has the disadvantage of making the learner more subject to the influence of "false friends".
In addition to positive transfer resulting in correct language production and negative transfer resulting in errors, there is some evidence that transfer from the first language can result in a kind of technical, or analytical, advantage over native speakers of a language. For example, second-language speakers of English whose first language is Korean have been found to be more accurate with perception of unreleased stops in English than native English speakers who are functionally monolingual because of the different status of unreleased stops in Korean from English. That "native-language transfer benefit" appears to depend on an alignment of properties in the first and the second languages that favors the linguistic biases of the first language.
Conscious and unconscious transfer
Language transfer may be conscious or unconscious. Consciously, learners or unskilled translators may sometimes guess when producing speech or text in a second language because they have not learned or have forgotten its proper usage. Unconsciously, they may not realize that the structures and internal rules of the languages in question are different. Such users could also be aware of both the structures and internal rules, yet be insufficiently skilled to put them into practice, and consequently often fall back on their first language. The unconscious aspect to language transfer can be demonstrated in the case of the so-called "transfer-to-nowhere" principle put forward by Eric Kellerman, which addressed language based on its conceptual organization instead of its syntactic features. Here, language determines how the speaker conceptualizes experience, with the principle describing the process as an unconscious assumption that is subject to between-language variation. Kellerman explained that it is difficult for learners to acquire the construal patterns of a new language because "learners may not look for the perspectives peculiar to the language; instead they may seek the linguistic tools which will permit them to maintain their L1 perspective."The conscious transfer of language, on the other hand, can be illustrated in the principle developed by Roger Andersen called "transfer-to-somewhere," which holds that "a language structure will be susceptible to transfer only if it is compatible with natural acquisitional principles or is perceived to have similar counterpart in the recipient language." This is interpreted as a heuristic designed to make sense of the target language input by assuming a form of awareness on the part of the learner to map L1 onto the L2. An analogy that can describe the differences between the Kellerman's and Anderson's principles is that the former is concerned with the conceptualization that fuels the drive towards discovering the means of linguistic expression whereas Andersen's focused on the acquisition of those means.
Acceleration and Deceleration
The theories of acceleration and deceleration are bilingual child language acquisition theories based on the known norms of monolingual acquisition. These theories come from comparisons of bilingual children's acquisition to that of their monolingual peers of similar backgrounds.Acceleration is a process similar to that of bootstrapping, where a child acquiring language uses knowledge and skills from one language to aid in, and speed up their acquisition of the other language.
Deceleration is a process in which a child experiences negative effects on their language acquisition due to interference from their other language.
In comprehension
Transfer can also occur in polyglot individuals when comprehending verbal utterances or written language. For instance, German and English both have relative clauses with a noun-noun-verb order but which are interpreted differently in both languages:German example: Das Mädchen, das die Frau küsst, ist blond
If translated word for word with word order maintained, this German relative clause is equivalent to
English example: The girl that the woman is kissing is blonde.
The German and the English examples differ in that in German the subject role can be taken by das Mädchen or die Frau while in the English example only the second noun phrase can be the subject. In short, because German singular feminine and neuter articles exhibit the same inflected form for the accusative as for the nominative case, the German example is syntactically ambiguous in that either the girl or the woman may be doing the kissing. In the English example, both word-order rules and the test of substituting a relative pronoun with different nominative and accusative case markings reveal that only the woman can be doing the kissing.
The ambiguity of the German NNV relative clause structure becomes obvious in cases where the assignment of subject and object role is disambiguated. This can be because of case marking if one of the nouns is grammatically male as in Der Mann, den die Frau küsst... vs. Der Mann, der die Frau küsst because in German the male definite article marks the accusative case. The syntactic ambiguity of the German example also becomes obvious in the case of semantic disambiguation. For instance in Das Eis, das die Frau isst... and Die Frau, die das Eis isst... only das Eis is a plausible object.
Because in English relative clauses with a noun-noun-verb structure the first noun can only be the object, native speakers of English who speak German as a second language are likelier to interpret ambiguous German NNV relative clauses as object relative clauses than German native speakers who prefer an interpretation in which the first noun phrase is the subject. This is because they have transferred their parsing preference from their first language English to their second language German.