In linguistics the term 'collocation' is used to mean a combination of lexical items that regularly or habitually occurs together, and sounds natural, in speech or writing. The way words combine in a language is not determined by rules of  syntax or grammar but is instead established through repeated context-dependent use within the language community. As a simple example: in Italian we say caffè forte and computer potente, but it would not be natural to say caffè potente or computer forte. Although collocations have become the subject of linguistic studies only relatively recently, they are attracting a growing interest among second language teachers and researchers. This because it is recognised that collocations are a key issue in clarity of expression. If collocational preferences are violated, even grammatically or syntactically correct sentences will sound unnatural and may even be unintelligible.  And, because different languages have different collocations, what collocates in one language does not necessarily collocate in another language. This means that errors of collocation are extremely common among second language learners. Normal dictionaries list some of the most common collocations, but more important is the publication of Italian collocation dictionaries specifically conceived to develop collocational competence. Using a collocation dictionary, the student naturally develops an increased range of vocabulary and facility of expression in idiomatic Italian.

Reference: Tiberii, P. : Dizionario italiano delle collocazioni. Le combinazioni delle parole in italiano. Bologna: Zanichelli, 2012

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