Summary of Code Mixing and Code Switching

Code mixing is combined two languages, or changes word, phrase or utterance to another language.
Code switching is change sentences to another language (keseluruhan)
Obvious change because the situations.

For example, suppose i know Hindi and English:
 Code switching: 

"Ram is a good boy aur bahut achchhi painting bhi karta hai."

Here the 1st part of the sentence is in English and second part is in Hindi, that is we have switched from English to Hindi.

 Code mixing:

"Ram is eating aam and playing with sita"

Here what happened, I am borrowing a word 'aam' (meaning Mango in English) from Hindi and adapting it in the English. Grammar of Hindi didn't get involve. Only lexical item of Hindi is embedded in English.

Code switching is a universal language-contact phenomenon that reflects the grammars of both languages working simultaneously.
Code mixing is also a language contact phenomenon that doesn't reflect the grammars of both languages working simultaneously. Here, we borrow words from one language and adapt it in other language.

Code switching and code mixing is possible in bilingual or multilingual environment, not in monolingual environment.
As because it is not possible to either switch or mix in the same language. At least two languages are needed for the above process to happen.
For instance, the bilingual children go through the mixing at their early stages of learning. While adults after becoming competent in at least 2 languages, they show their performance of their learning by switching from one language to another.

Summary dialect and varieties

A dialect is a regional or social variety of a language distinguished bypronunciation, grammar, and/orvocabulary. Adjective: dialectal.

The term dialect is often used to characterize a way of speaking that differs from the standard variety of the language. Nonetheless, as David Crystal explains below, "Everyone speaks a dialect."

The scientific study of dialects is known as dialectology, commonly regarded as a subfield of sociolinguistics.

What's the Difference Between a Language and a Dialect?
"The very fact that 'language' and 'dialect' persist as separate concepts implies that linguists can make tidy distinctions for speech varieties worldwide. But in fact, there is no objective difference between the two: Any attempt you make to impose that kind of order on reality falls apart in the face of real evidence. . . .

"English tempts one with a tidy dialect-language distinction based on 'intelligibility': If you can understand it without training, it’s a dialect of your own language; if you can’t, it’s a different language. But because of quirks of its history, English happens to lack very close relatives, and the intelligibility standard doesn’t apply consistently beyond it. . . .

What's the Difference Between a Dialect and an Accent?
"Accents have to be distinguished from dialects. An accent is a person's distinctive pronunciation. A dialect is a much broader notion: it refers to the distinctive vocabulary and grammar of someone's use of language. If you say eether and I sayiyther, that's accent. We use the same word but pronounce it differently. But if you say I've got a new dustbin and I say I've gotten a new garbage can, that's dialect. We're using different word and sentence patterns to talk about the same thing."

Summary pidgin and creole languages

A pidgin is a restricted language which arises for the purposes of communication between two social groups of which one is in a more dominant position than the other. The less dominant group is the one which develops the pidgin.

Historically, pidgins arose in colonial situations where the representatives of the particular colonial power, officials, tradesmen, sailors, etc., came in contact with natives. The latter developed a jargon when communicating with the former. This resulted in a language on the basis of the colonial language in question and the language or languages of the natives. Such a language was restricted in its range as it served a definite purpose, namely basic communication with the colonists. In the course of several generations such a reduced form of language can become more complex, especially if it develops into the mother tongue of a group of speakers. This latter stage is that of creolisation. Creoles are much expanded versions of pidgins and have arisen in situations in which there was a break in the natural linguistic continuity of a community, for instance on slave planatations in their early years.

A pidgin language is a mixed language that enables limited communication between two groups that don’t share a common language. So that is the advantage.

The disadvantages are that the languages are limited, e.g. to trade, and that they have to be created over time.

Some languages that are referred to as pidgins are in fact creoles, which are full languages derived from pidgins. They are comparable to any other natural language in terms of pros and cons

Register is a style or variety of language determined by such factors as social occasion,context, purpose, and audience, also called stylistic variation. Practically, the term refers to the degrees of formality with which populations use language; these formal variations are sometimes called codes.

Registers are marked by a variety of specialized vocabulary and turns of phrases, colloquialisms and the use of jargon, and a difference in intonation and pace; in "The Study of Language," linguist George Yule describes the function of jargon as helping " to create and maintain connections among those who see themselves as 'insiders' in some way and to exclude 'outsiders.'"