Until recently, theoretical linguists have paid little attention to the frequency of linguistic elements in grammar and grammatical development. It is a standard assumption of (most) grammatical theories that the study of grammar (or competence) must be separated from the study of language use (or performance). However, this view of language has been called into question by various strands of research that have emphasized the importance of frequency for the analysis of linguistic structure. In this research, linguistic structure is often characterized as an emergent phenomenon shaped by general cognitive processes such as analogy, categorization, and automatization, which are crucially influenced by frequency of occurrence.
There are many different ways in which frequency affects the processing and development of linguistic structure. Historical linguists have shown that frequent strings of linguistic elements are prone to undergo phonetic reduction and coalescence, and that frequent expressions and constructions are more resistant to structure mapping and analogical leveling than infrequent ones. Cognitive linguists have argued that the organization of constituent structure and embedding is based on the language users’ experience with linguistic sequences, and that the productivity of grammatical schemas or rules is determined by the combined effect of frequency and similarity. Child language researchers have demonstrated that frequency of occurrence plays an important role in the segmentation of the speech stream and the acquisition of syntactic categories, and that the statistical properties of the ambient language are much more regular than commonly assumed. And finally, psycholinguists have shown that structural ambiguities in sentence processing can often be resolved by lexical and structural frequencies, and that speakers’ choices between alternative constructions in language production are related to their experience with particular linguistic forms and meanings. Taken together, this research suggests that our knowledge of grammar is grounded in experience.