Language interference (also known as linguistic interference, cross-linguistic interference or transfer) is the effect of a language learner’s first language on their production of the language they are learning. The effect can be on any aspect of language: grammar, vocabulary, accent, spelling etc. It is most often discussed as a source of errors (negative transfer), although where the relevant feature of both languages is the same, it results in correct language production (positive transfer). The greater the differences between the two languages, the more negative the effects of interference are likely to be. Interference is most commonly discussed in the context of ESL teaching, but it will inevitably occur in any situation where someone has an imperfect command of a second language.

Mechanism

Interference may be conscious or unconscious. Consciously, the student may guess because he has not learned or has forgotten the correct usage. Unconsciously, the student may not consider that the features of the languages may differ, or he may know the correct rules but be insufficiently skilled to put them into practice, and so fall back on the example of his first language.

Multiple acquired languages

Interference can also take place between acquired languages: an English learner of French and Spanish, for example, may mistakenly assume that a particular feature of one language applies also to the other.

Engrish

Language interference produces distinctive forms of learner English depending on the speaker’s first language. Some well-known examples are: Engrish or Japlish (Japanese); Spanglish (Spanish); Franglais (French); Chinglish (Chinese) and Tinglish (Thai).

Positive transfer

The positive aspects of language interference are less often discussed, but they can be very important. Generally the process will be more positive the closer the two languages are, and the more the learner is aware of the relationship between the two languages. Thus, an English learner of German may well correctly guess an item of German vocabulary from its English equivalent, but the word order is more likely to differ. This approach has the disadvantage that it makes the learner more subject to the influence of false friends.

Wider effects

Language interference in immigrant communities can break out of those communities and affect the native-speaking population. One example of this is the use of "hopefully", as in the sentence "Hopefully, it won’t be a problem", which derives from the German use of hoffentlich.