least two levels of representation: underlying representation and surface phonetic representation. Ordered phonological rules govern how underlying representation Phonology (formerly also phonemics or phonematics) is the branch of linguistics that concerns how languages organize the foundational elements that make their words. In spoken languages, these are phonemes like vowel and consonant sounds that affect meaning. Examples of this effect can be found in comparisons of English words like bat and gnat. In sign languages, these are components of signs such Part of the phonological study of a language therefore involves looking at data (phonetic transcriptions of the speech of native speakers) and trying to deduce what the underlying phonemes are and what the sound inventory of the language is. The presence or absence of minimal pairs, as mentioned above, is a frequently used criterion for deciding whether two sounds should be assigned to the same phoneme. However, other considerations often need to be taken into account as well. The particular contrasts which are phonemic in a language can change over time. At one time, [f] and [v], two sounds that have the same place and manner of articulation and differ in voicing only, were allophones of the same phoneme in English, but later came to belong to separate phonemes. This is one of the main factors of historical change of languages as described in historical linguistics. The findings and insights of speech perception and articulation research complicate the traditional and somewhat intuitive idea of interchangeable allophones being perceived as the same phoneme. First, interchanged allophones of the same phoneme can result in unrecognizable words. Second, actual speech, even at a word level, is highly co-articulated, so it is problematic to expect to be able to splice words into simple segments without affecting speech perception. Different linguists therefore take different approaches to the problem of assigning s Directly influenced by Baudouin de Courtenay, Trubetzkoy is considered the founder of morphophonology, but the concept had also been recognized by de Courtenay. Trubetzkoy also developed the concept of the archiphoneme. Another important figure in the Prague school was Roman Jakobson, one of the most prominent linguists of the 20th century. Louis Hjelmslev's glossematics also contributed with a focus on linguistic structure independent of phonetic realization or semantics. In 1968, Noam Chomsky and Morris Halle published The Sound Pattern of English (SPE), the basis for generative phonology. In that view, phonological representations are sequences of The features were an expansion of earlier work by Roman Jakobson, Gunnar Fant, and Morris Halle. The features describe aspects of articulation and perception, are from a universally fixed set and have the binary values + or −. There are at least two levels of representation: underlying representation and surface phonetic representation. Ordered phonological rules govern how underlying representation is transformed into the actual pronunciation (the so-called surface form). An important consequence of the influence SPE had on phonological theory was the downplaying of the syllable and the emphasis on segments. For example, in Thai, Bengali, and Quechua, there are minimal pairs of words for which aspiration is the only contrasting feature (two words can have different meanings but with the only difference in pronunciation being that one has an aspirated sound where the other has an unaspirated one). Part of the phonological study of a language therefore involves looking at data (phonetic transcriptions of the speech of native speakers) and trying to deduce what the underlying phonemes are and what the sound inventory of the language is. The presence or absence of minimal pairs, as mentioned above, is a frequently used criterion for deciding whether two sounds should be assigned to the same phoneme. However, other considerations often need to be taken into account as well. The particular contrasts which are phonemic in a language can change over time. At one time, [f] and [v], two sounds that have the same place and manner of articulation and differ in voicing only, were allophones of the same phoneme in English, but later came to belong to separate phonemes. This is one of the main factors of historical change of languages as described in historical linguistics. The findings and insights of speech perception and articulation research complicate the traditional and somewhat intuitive idea of interchangeable allophones being perceived as the same phoneme. First, interchanged allophones of the same phoneme can result in unrecognizable words. Second, actual speech, even at a word level, is highly co-articulated, so it is problematic to expect to be able to splice words into simple segments without affecting speech perception. Different linguists therefore take different approaches to the problem of assigning sounds to phonemes. For example, they differ in the extent to which they require allophones to be phonetically similar. There are also differing ideas as to whether this grouping of sounds is purely a tool for linguistic analysis, or reflects an actual process in the way the human brain processes a language. 1–30). Kenstowicz, Michael. Phonology in generative grammar. Oxford: Basil Blackwell. Ladefoged, Peter. (1982). A course in phonetics (2nd ed.). London: Harcourt Brace Jovanovich. Martinet, André (1949). Phonology as functional phonetics. Oxford: Blackwell. Martinet, André (1955). Économie des changements phonétiques: Traité de phonologie diachronique. Berne: A. Francke S.A. Napoli, Donna Jo (1996). Linguistics: An Introduction. New York: Oxford University Press. Pike, Kenneth Lee (1947). Phonemics: A technique for reducing languages to writing. Ann Arbor: University of Michigan Press. Sandler, Wendy and Lillo-Martin, Diane. 2006. Sign language and linguistic universals.