Methods for Measuring Intelligibility of Closely Related Language Varieties

Introduction The exact number of known living languages varies from 5,000 to 10,000, depending on one's definition of 'language'. An even larger number of dialects are spoken worldwide. Many of these languages and dialects (from now on taken together as 'languages' or 'varieties') are so similar that they are mutually intelligible to varying degrees, even without prior contact or formal instruction. Speakers of such different yet related languages sometimes communicate each speaking their own language. Haugen (1966) introduced the term semicommunication for this kind of communication. Other terms used are receptive multilingualism, semibilingualism, non-convergent discourse, asymmetric/bilingual discourse, and inherent intelligibility. Examples of observed semicommunication can be found in Zeevaert (2004). For various reasons it may be interesting to establish the degree to which a speaker of one variety understands the speech of another closely related variety, for instance to resolve issues that concern language planning and policies, second language learning, and language contact. Unbiased data about distances between varieties and detailed knowledge about intelligibility can also be critical for sociolinguistic studies. Varieties that have strong social stigmas attached to them could unrightfully be deemed hard to understand (Wolff 1959; Giles & Niedzielski 1998). The relationship between attitudes and intelligibility is not a straight forward one, but advances in the field of linguistic distances and intelligibility testing provide sociolinguists with objective data to resolve conflicts that arise concerning varieties on a standard-nonstandard continuum. Knowledge about mutual intelligibility is also needed for standardisation and development of new orthographies in communities where no standardised orthography exists. To investigate intelligibility, a large number of tests have been developed that make it possible to express degree of intelligibility in a single number, often the percentage of input that was correctly recognized by the subject. The aim of the present chapter is to give an overview of methods for measuring intelligibility of closely related languages and to discuss the advantages and disadvantages of the various methods. We focus on spoken language comprehension, but many tests can also be applied to the comprehension of written language. The experimental and methodological considerations relevant for intelligibility testing have a great deal in common with those relevant for studies in various other areas of sociolinguistics. For example, efforts must generally be taken to control the context of speech production or speech perception as much as possible while keeping the recording or listening condition as natural as possible. A number of …