Wardhaugh (1986: 102) says that code is the particular dialect or language one chooses to use on any occasion, and a system for communication between two or more parties. Poedjosoedarmono (1978: 4) says that a code is a system of speech whose elements of language has special characteristic, and it is proper to the background of the speaker, the relation of the speaker to address and the situation. Another linguistic phenomenon in bilingual or multilingual society is code mixing. Code switching and code mixing are terms that are used to call the dependence upon aspect of language. The difference of those terms that can be found is the dependence indicating characteristics. In the phenomenon of code mixing the dependent characteristics are indicated by the relationship between the function and role of language. The role means that who uses the language and function means what will be acquired by the speaker (Suwito in Sutana 1999: 17).
Mackey in Suwito (1985: 65) states that Code Mixing is one characteristic of language dependence. Then, He cities that the language dependence is marked by the presence of reciprocal relations between roles and language functions. According to him, the roles refer to who uses language, whereas the language functions refer to what will bed achieve by speaker in his utterances. So if a speaker mixes two different codes on language in his utterances, then it should be asked first who he is.
In this manner, the specific characteristics of the speaker are, among others, his social background, level of education and solidarity of region. However, all of these specific characteristics will often color his code mixing. On the other hand, the language unction determines how far the languages used by speaker give an opportunity to mix codes. Finally, a speaker who masters many languages will have a greater opportunity to mix codes, because what a speaker of his utterance achieves is extremely determined by his language choice.
Code mixing usually occurs in bilingual or multilingual community or society and the function (meaning) of the languages can not be clearly separated. This code mixing is used when the conversant use both languages together to the extent that they change from one language to the other in the course of a single utterance (Wardhaugh, 1986: 103)
In code mixing the main code or basic code has its own function and meaning, other codes, however, are only the pieces, without function and meaning as a code (Chaer, 1995: 151). Thelander (In Chaer, 1995: 152) explains the definition of code mixing. He says that if in the single utterance the clauses and the phrases used are hybrid clause or hybrid phrases and each clause or phrase does not support the function of clause and phrase, it is called code mixing. The special character of code mixing is that, code mixing is used in informal situation. In the formal situation it may have no exact meaning in Indonesian language. In the written language code mixing is indicated by italic writing or underline form (Nababan, 1984: 32).
Another aspect of dependent relation of language in multilingual people is the phenomenon of code mixing in context of function of switch, the relevance of situation is the form of dependence identified from both sides of relationships between speakers and the function of language.
Code mixing has two features, namely dependency feature and the language or variant elements that insert in other language have no more function. Dependency feature marked by the relationship between the language rule and function. The role means who use the language and function means what will be reached by the speaker with his or her utterance. If the speaker mixes his or her code or language, then it must be asked the factors such as: who the speaker is: social background, the level of education, religion, etc. A speaker who masters many languages will have chance to mix code more than the other speakers who only master one language. But it does not mean that the speaker who masters many languages will always mix codes.
The second feature that the language or variant elements inserted in other language have no more function. It can be classified into two kinds. The first is inner code mixing that is originated from the native language with its all variations, for instance Jawa Ngoko mixed with Jawa Krama- Inggil, wah baksone pun telas mas, pados liyane mawon. In this sentence, the speaker mixes jawa ngoko, liyane, with jawa krama inggil, pun, telas, mawon.
The second is outer code mixing that mix a foreign language with native language such as English language mixed with Indonesian language. Saya sedang tidak bisa berpikir, otakku blank. In this sentence, the speaker mixes English language, blank, with Indonesian language saya, sedang, tidak, bisa, berpikir, otakku.
Sometimes, people consider that code switching and code mixing have the same meaning. But actually both of them are different. People in the bilingualism or multilingualism situation often change language or variety of languages. This situation depends on situation or the need for communication such as when a person uses a standard language when he meets his guest. When he knows that, actually, the guest is his old friend, the person switches his standard language into informal language. This phenomenon is called code switching.
According to Crystal (1991: 59) code switching can be illustrated by the switch bilingual speaker may make (depending on who they are talking to or where they are) between standard and regional forms of English, between Welsh and English in parts of Wales, or between occupational and domestics varieties.
Komarudin (1989: 59) says that code switching occurs in level of clauses and sentences. Code switching is general characteristics in bilingualism. Bilingual people often switch codes from one language to other language when they speak or write.
Code switching is switching situation from one code to another (Suwito, 1985: 68). If a speaker firstly uses code A (for example Indonesian Language) and he changes his code to code B (Javanese Language), this situation is called code switching.
Code switching not only occurs in the form of language change but also may happen in the change of the variant of language. Hymes (in Chaer 1995: 142) says that code switching has become a common term for alternate us of two or more languages, varieties of language or even speech style. For example, when people switch one code, in example, grammatical code to casual code when the situation changes into informal situation.
Code switching happens in bilingual society. Code switching occurs when people use a particular code and suddenly change to another code. Apple (in Chaer 1995: 141) states code switching is the change of one code to another. Wardhaugh (1986: 103) also gives definition of code switching occurs when the language used, changes according to the situation in which the conversant find them selves. The speakers here switch one code to another code or they speak in one language to another language.
Code-switching is a term in linguistics referring to using more than one language or dialect in conversation. Code-switching can occur between sentences (intersentential) or within a single sentence (intrasentential). Code-switching is now considered to be a normal and natural product of interaction between the bilingual (or multilingual) speaker’s two languages. Code-switching can be distinguished from other language contact phenomena such as loan translation (calques), borrowing, pidgins and creoles, and transfer or interference.