A loanword (or loan word) is a word borrowed from one language and incorporated into another.
The word loanword is itself a calque of the German Lehnwort, while calque is a loanword from French.
Loanwords can also be called "borrowings". Although of long-standing usage, neither loanword nor borrowing correctly conveys the meaning, since no words are going to be returned to the "creditor" language.
Certain classes of words are more commonly borrowed than others, usually words for exotic concepts or ideas. What is "exotic" varies from language to language. Thus, English names for creatures not native to Great Britain are almost always loanwords, and most of the technical vocabulary referring to classical music is borrowed from Italian.
By contrast, function words such as pronouns, numbers, and words referring to universal concepts, are usually not borrowed, but have been in some cases (e.g., English they from Old Norse þeir).
The studies by Werner Betz (1949, 1959), Einar Haugen (1950, also 1956), and Uriel Weinreich (1953) are regarded as the classical theoretical works on loan influence. The basic theoretical statements all depart from Betz’s nomenclature. Duckworth (1977) enlarges Betz’s scheme by the type “partial substitution” and supplements the system with English terms:
foreign word = non-integrated word from a foreign language, spelt as is, e.g. E café (from French); Sp. whisk(e)y (from English) (*the word whiskey in fact comes from the Irish phrase "uisce beatha" which means the water of life, "aqua vitae"); E weltanschauung (< G Weltanschauung); It. mouse ‘computer device’ (< E mouse ‘rodent; computer device’).
loan word = integrated word from a foreign language, orthography adapted for the receiving language, e.g. E music (from French "musique"); Sp. chófer (from French "chauffeur").
partial substitution: composite words, in which one part is borrowed, another one substituted, e.g. OE Saturnes dæg ‘Saturday’ (< Lat. Saturni dies), G Showgeschäft ‘literally: show-business’ (< E show business), G Live-Sendung ‘literally: live-broadcast’ (< E live broadcast).
loan translation = translation of the elements of the foreign word, e.g. OE Monan dæg ‘Monday’ (< Lat. Lunae dies), Fr. gratte-ciel and Sp. rasca·cielos ‘both literally: scrape-sky’ (< E skyscraper), E world view (< G Welt·anschauung), AmSp. manzana de Adán (< E Adam’s apple; vs. EurSp. nuez [de la garganta] ‘literally: nut [of the throat]’).
loan rendering = translation of part of the elements of the foreign word, e.g. E brother·hood (< Lat. frater·nitas [= Lat. frater ‘brother’ + suffix]); G. Fernsehen(literally "far seeing"), translating elements of E. television or F. télévision, the first element Gk. telos "far" and the second L. visio "sight".
loan creation coinage independent of the foreign word, but created out of the desire to replace a foreign word, e.g. E brandy (< Fr. cognac).
loan meaning = indigenous word to which the meaning of the foreign word is transferred, e.g. OE cniht ‘servant + disciple of Jesus’ (< Lat. discipulus ‘student, disciple of Jesus’), OE heofon ‘sky, abode of the gods + Christian heaven’ (< Lat. caelum ‘sky, abode of the gods, Christian heaven’), G Maus and Fr souris ‘rodent + computer device’ (< E mouse ‘rodent, computer device’).
On the basis of an importation-substitution distinction, Haugen (1950: 214f.) distinguishes three basic groups of borrowings: “(1) Loanwords show morphemic importation without substitution. [. . .]. (2) Loanblends show morphemic substitution as well as importation. [. . .]. (3) Loanshifts show morphemic substitution without importation”. Haugen has later refined (1956) his model in a review of Gneuss’s (1955) book on Old English loan coinages, whose classification, in turn, is the one by Betz (1949) again.
Weinreich (1953: 47ff.) differentiates between two mechanisms of lexical interference, namely those initiated by simple words and those initiated by compound words and phrases. Weinreich (1953: 47) defines simple words “from the point of view of the bilinguals who perform the transfer, rather than that of the descriptive linguist. Accordingly, the category ‘simple’ words also includes compounds that are transferred in unanalysed form”. After this general classification, Weinreich then resorts to Betz’s (1949) terminology.
Models that try to integrate borrowing in an overall classification of vocabulary change, or onomasiological change, have recently been proposed by Peter Koch (2002) and Joachim Grzega (2003, 2004).
Ghil'ad Zuckermann's analysis of multisourced neologization (2003) challenges Einar Haugen's classic typology of lexical borrowing . While Haugen categorizes borrowing into either substitution or importation, Zuckermann explores cases of "simultaneous substitution and importation" in the form of camouflaged borrowing. He proposes a new classification of multisourced neologisms, words deriving from two or more sources at the same time. Examples of such mechanisms are phonetic matching, semanticized phonetic matching and phono-semantic matching. Phono-semantic matching is distinct from calquing. While calquing includes (semantic) translation, it does not consist of phonetic matching (i.e. retaining the approximate sound of the borrowed word through matching it with a similar-sounding pre-existent word/morpheme in the target language).
Idiomatic expressions and phrases, sometimes translated word-for-word, can be borrowed, usually from a language that has "prestige" at the time. Often, a borrowed idiom is used as a euphemism for a less polite term in the original language. In English, this has usually been Latinisms from the Latin language and Gallicisms from French. If the phrase is translated word-for-word, it is known as a calque.
English has many loanwords. In 1973, a computerised survey of about 80,000 words in the old Shorter Oxford Dictionary (3rd edition) was published in Ordered Profusion by Thomas Finkenstaedt and Dieter Wolff. Their estimates for the origin of English words were as follows:
French and Norman, including Old French, Old Norman, Anglo-French and Anglo-Norman: 28.3%
Latin, including modern scientific and technical Latin: 28.24%
Germanic languages, including Old and Middle English: 25%
No etymology given or unknown: 4.03%
Derived from proper names: 3.28%
All other languages contributed less than 1%
The reasons for English's vast borrowing include: (to a relatively small extent) the existence of other languages native to Britain;
the invasion of England by the Vikings and the Normans, and continuing French influence;
borrowings and new coinages from Latin and Greek, as in other European languages;
cultural openness to borrowing; and
its modern global importance.
The flexibility of English's syllable structure, while possibly a contributing factor, is certainly not essential – languages with very restricted syllable structures such as Japanese borrow a similarly large portion of their vocabulary.
The lack of restrictions on the syllable structure does mean that words do not usually need to be heavily modified in borrowing, though due to phonemic and phonetic differences, the English pronunciations of loanwords often differ from the original pronunciations to such a degree that a native speaker of the language it was borrowed from is not able to recognize it as a loanword when spoken.
English has often borrowed words from the cultures and languages of the British Colonies. For example, words borrowed from Hindi include syce/sais, dinghy, chutney, pundit, wallah, pajama/pyjamas, bungalow and jodhpur. Other examples include: trek, aardvark, laager, wildebeest and veld from Afrikaans; orangutan, shirang, amok from (Malay); and sjambok via Afrikaans from Malay.
English also acquires loanwords in which foreign sounds are part of the foreign pronunciation. For example, the Hawaiian word ʻaʻā is used by geologists to specify lava that is relatively thick, chunky, and rough. The Hawaiian spelling indicates the two glottal stops in the word, but the English pronunciation, [ˈɑː.ɑː] or [ˈɑːʔɑː], contains at most one. In addition, the English spelling usually removes the okina and macron diacritics.
The majority of English affixes, such as "un-", "-ing", and "-ly", were present in older forms in Old English. However, a few English affixes are borrowed. For example, the agentive suffix -er, which is very prolific, is borrowed ultimately from Latin. The English verbal suffix -ize comes from Greek -ιζειν via Latin -izare.
Direct loans, expressions translated word-by-word, or even grammatical constructions and orthographical conventions from English are called anglicisms. Similarly, loans from Swedish - like the word smörgåsbord - are called sveticisms or svecisms. In French, the result of perceived over-use of English loanwords and expressions is called franglais. English loanwords in French include 'le weekend', 'le job' (in France) or 'la job' (in Canada) and 'la bifteck' (beefsteak). Denglisch is English influence on German. Another popular term is Spanglish, the English influence on the Spanish language and Dunglish the English influence on the Dutch language. The mix of Spanish and Catalan words or grammar structures in a sentence is called Catanyol (CATalan-espANYOL).
During the Ottoman period, Turkish literature became heavily influenced by Persian and Arabic borrowings. During more than 600 years of the Ottoman Empire, the literary and official language of the empire was a mixture of Turkish, Persian, and Arabic, which is now called Ottoman Turkish, considerably differing from the everyday spoken Turkish of the time. Many Turkish, Persian and Arabic words were also loaned to other languages of the empire, such as Bulgarian and Serbian. After the empire fell in World War I and the Republic of Turkey was founded, the Turkish language underwent an extensive language reform led by the newly founded Turkish Language Association, during which many loanwords were replaced with equivalent words derived from Turkic roots. The language reform was a part of the ongoing cultural reform of the time, in turn a part in the broader framework of Atatürk's Reforms, and included the introduction of the new Turkish alphabet. Turkish also has many loanwords derived from French, such as pantalon for 'trousers' and komik for 'funny' (from Fr. comique), all of them pronounced very similarly (except for the French pronunciation of the letter 'r').
The Italian government has recently expressed its displeasure over the borrowing of English words and syntax in Italian. English words are often used where they are more convenient than a longer Italian expression, as in "computer" for elaboratore elettronico or "week-end" for finesettimana; but also where equally convenient Italian words already exist, as in "fashion" for moda and "meeting" for conferenza.
Words are occasionally borrowed with a different meaning than the meaning in the source language. Among the best known examples of this is the German word Handy, which is a borrowing of the English adjective handy, but means mobile phone and is thus a noun. Conversely, in English the prefix über-, taken from German, is used in a way that it is rarely used in German.
Words borrowed into different languages are sometimes spelled as in the original language (such as many of the loanwords above). Sometimes loanwords retain original (or near-original) pronunciation, but undergo a spelling change to represent the orthography of the adopting language. Welsh is a language where this is done with some consistency, with words like gêm (game), cwl (cool), and ded-gifawe (dead giveaway).
Some languages, such as Jèrriais, have a tendency to apply historical sound-shift patterns to new borrowed words; while Jèrriais speakers would have little difficulty pronouncing "parki", partchi (to park) is the word used, displaying the typical Norman ki->tchi shift.
Most languages modify loanwords to fit native pronunciation patterns. An excellent example is Japanese, which has an enormous number of loanwords (gairaigo). Ignoring ancient influence from China, recently most Gairaigo have come from English, though there have been significant borrowings from Dutch, German and other languages. There are almost always significant pronunciation shifts (volleyball ->(バレーボール, barēbōru)). Longer terms often are shortened (Automotive navigation system -> Car navigation system (カーナビ, kānabi)). In some cases the original meaning shifts considerably through unexpected logical leaps (buffet -> (バイキング, baikingu (Viking)): derived from the name of the restaurant "Imperial Viking", the first restaurant in Japan which offered buffet style meal). In other cases words are borrowed, seemingly at random, and used in totally inexplicable contexts. This is often the case in the names of small businesses, and in anime and manga series such as Bubblegum Crisis. Gairaigo is so large a part of the modern Japanese vocabulary that there are specialized dictionaries for it.
It is possible for a word to travel from one language to another and then back to the original language in a different form, a process called reborrowing. A specific example of this is the French "le biftek", which is borrowed from the English "beefsteak", while the English "beef" is originally from the Norman (cf. French "le bœuf").
Another example of this is found in Northern Africa where the Spanish word "Zapato" is used for the word shoe. However, the word "Zapato" came from the Arabic word for shoe: "Sabbat" (سباط) which was borrowed by the Spanish when the Islamic Arabs were living in Andalusia (modern day Spain).
Finally, another example is the word cinema which is based on Greek word for movement, κίνημα (transliteration: kinima), but has been re-borrowed by modern Greek as σινεμά (transliteration: sinema) (Wikipedia)