Mutual intelligibility

In linguistics, mutual intelligibility is recognized as a relationship between languages in which speakers of different but related languages can readily understand each other without intentional study or extraordinary effort. It is sometimes used as one criterion for distinguishing languages from dialects, though sociolinguistic factors are also important.

Intelligibility between languages can be asymmetric, with speakers of one understanding more of the other than speakers of the other understand of the first. It is when it is relatively symmetric that it is characterized as 'mutual'. It exists in differing degrees among many related or geographically proximate languages of the world, often in the context of a dialect continuum.

Intelligibility
For individuals to achieve moderate proficiency or understanding in a language (called L2) other than their mother tongue or first language (L1) typically requires considerable time and effort through study and/or practical application. However, for those many groups of languages displaying mutual intelligibility, namely, those, usually genetically related languages, similar to each other in grammar, vocabulary, pronunciation, or other features, speakers of one language usually find it relatively easy to achieve some degree of understanding in the related language(s). Languages mutually intelligible but not genetically related may be creoles and parent languages, or geographically adjacent variants of two unrelated languages.

Intelligibility among languages can vary between individuals or groups within a language population, according to their knowledge of various registers and vocabulary in their own language, their interest in or familiarity with other cultures, psycho-cognitive traits, and other factors.

Mutually intelligible languages or variants of one language?
According to some definitions, two or more languages that demonstrate a sufficiently high degree of mutual intelligibility should properly not be considered two distinct languages but, in fact, multiple variants of the same language. Conversely, it is sometimes the case that different varieties of what is considered the same language—according to popular belief, governmental stance, or historical convention—are not, in fact, mutually intelligible in practice. (For more on this, see Dialect, and Dialect continuum—as well as Diasystem and Diglossia for two closely related but distinct language forms.)

Examples

 * Varieties of Chinese
 * Differences between Malay and Indonesian
 * Differences between Norwegian Bokmål and Standard Danish
 * Differences between Scottish Gaelic and Irish
 * Differences between Afrikaans and Dutch
 * Differences in standard Serbian, Croatian and Bosnian
 * Differences between Spanish and Portuguese
 * Differences between Hindi and Urdu
 * Differences between Slovak and Czech