Comparing Code-Switching and Code-Mixing 

Code-switching and code-mixing, are characteristics associated with bilinguals. A bilingual is someone who has mastery or a level of competence in the use of two languages. A person that is capable of alternating between codes. A bilingual's control of two languages affords them the liberty to alternate between codes in the course of a discourse, and this is where code switching, and code mixing come in.

Code switching 

Code switching, is a bilingual characteristics that involves a diversion from one language to another in the course of an utterance. It is a switch from one code or language to another, that does not take place in a sentence.

For example; I will eat the food. Aguru n'agu m.

The switch from the English language to the Igbo language occurs in different sentences. However, there are instances where an utterance in a different language may be embeded in a language. To illustrate:

I want to eat goat meat —"Isi Ewu".

The switch from the English language to the Igbo language occurs in the same utterance, but the lexical items in Igbo language are placed in quotation marks to signal that there have been a switch from the English language, to the Igbo language. The items in Igbo simply reiterate —goat meat.

Furthermore, code switching occurs, when there is a diversion from one language to another, where the switch occurs at the end of the language with which the conversation, was started. To illustrate this;

I want to eat goat meat —"Isi Ewu".

The switch does not occur in the middle of the utterance in the first language, but at the termination, or final position. 

Reasons why people code switch

People code switch for a number of reasons;

1. To exclude outsiders from a conversation: Depending on the field of discourse, or the topic being discussed, interlocutors might code switch for the purpose of excluding outsiders from their conversations. Especially when what is being discussed is a very delicate or private issue which the discussants would rather not disclose. For example; bilingual adults might code switch when discussing adult-rated topics in front of younger children due to their innocence.

2. To show affiliation: Bilinguals usually code switch to show affiliation with speakers of their language. For example; an Igbo man conversing with a fellow Igbo man in the English language might choose to momentarily switch from the English language to the Igbo language to deepen their level of familiarity, and create a strong sense of kinship and oneness.

3. To emphasize a point: Popular in the African continent, bilinguals often code switch for the purpose of re-emphasizing what had already been said in another language. For example; a bilingual African parent instructing their child on what to do might code switch from the English language to an African language, just to be as clear as possible in issuing an instruction.

4. To introduce a native joke: This is one of the many peculiarities of being a bilingual. Bilinguals may oftentimes, code switch from one language to another, just to introduce a joke that would not be fully realized in the language of their conversation. For example; Hausa men conversing in the English language might choose to code switch to introduce a joke, or even a saying that can only be fully realized in their native language, or that only has expression in their native language.

5. To quote a person: Finally, bilinguals often code switch for the purpose of quoting what a person had said at a point in time in a different language. For example; bilinguals discussing in the English language might choose to code switch for the purpose of introducing a quote, what someone had said, in their indigenous language.

Code mixing 

Code mixing, is closely related to code switching. In fact, most people use both terms interchangeably as they are unable to draw a clear cut distinction between them. Code mixing, as the name implies, is a mixture of elements of one language with that of another language. Now, unlike in code switching, code mixing is not a total diversion from one language to another, but can be likened to a momentary borrowing of words from one language into a conversation in a different language.

For example: She is so belle to be standing in the sun.

See also: The scope of bilingualism 

The inclusion of the french lexical item "belle", in the English themed utterance, is a good example of code mixing. An instance where a word from a different language is inserted in an utterance in the course of a discourse, is code mixing. The word from a different language that gets mixed with an utterance in a language does not occur at the end of the utterance, like in code switching where the new code begins at the termination of the former.

It is an occasional borrowing of a lexical item from one language into a conversation, in a different language, either to show familiarity, to embed native flavours into a conversation, or simply for the purpose of emphasis, as the case may be.

Code switching is not to be used interchangeably with code mixing, because, even though they are similar concepts, they vary in approach. While code switching is a total diversion from one language to another in a discourse, code mixing is a blending of two languages, where a lexical item from one language is inserted in an utterance of another language.