In linguistics, productivity is the degree to which speakers of a language use a particular grammatical process, especially in word formation. It compares grammatical processes that are in frequent use to less frequently used ones that tend towards lexicalization. Generally the test of productivity concerns identifying which grammatical forms would be used in the coining of new words: these will tend to only be converted to other forms using productive processes. Examples in English In standard English, the formation of preterite and past participle forms of verbs by means of ablaut (as Germanic strong verbs, for example, sing–sang–sung) is no longer considered productive. Newly coined verbs in English overwhelmingly use the 'weak' (regular) ending -ed for the past tense and past participle (for example, spammed, e-mailed). Similarly, the only clearly productive plural ending is -(e)s; it is found on the vast majority of English count nouns and is used to form the plurals of neologisms, such as FAQs and Muggles. The ending -en, on the other hand, is no longer productive, being found only in oxen, children, and the now-rare brethren (as a plural of brother). Because these old forms can sound incorrect to modern ears, regularization can wear away at them until they are no longer used: brethren has now been replaced with the more regular-sounding brothers except when talking about religious orders. It appears that many strong verbs were completely lost during the transition from Old English to Middle English, possibly because they sounded archaic or were simply no longer truly understood. In both cases, however, occasional exceptions have occurred. A false analogy with other verbs caused dug to become thought of as the 'correct' preterite and past participle form of dig (the King James Bible preferred digged in 1611) and more recent examples, like snuck from sneak and dove from dive, have similarly become popular. Some American English dialects also use the non-standard drug as the past tense of drag. Significance Since use to produce novel (new, non-established) structures is the clearest proof of usage of a grammatical process, the evidence most often appealed to as establishing productivity is the appearance of novel forms of the type the process leads one to expect, and many people would limit the definition offered above to exclude use of a grammatical process that does not result in a novel structure. Thus in practice, and, for many, in theory, productivity is