The essential difference between grammar and lexicon is the following: The grammar is concerned with those signs which are formed regularly and which are handled analytically, while the lexicon is concerned with those signs which are formed irregularly and which are handled holistically. A sign is lexicalized if it is withdrawn from analytic access and inventorized. On the other hand, for a sign to be grammaticalized means for it to acquire functions in the analytic formation of more comprehensive signs. Both processes regularly, but not necessarily involve a reductive component. Consequently, grammaticalization is not the mirror image of lexicalization.

　　The genesis of members of minor word classes, in particular adpositions and conjunctions, has often been treated as an instance of grammaticalization. However, minor word classes are not necessarily classes of grammatical formatives. In particular, there are more lexical and more grammatical adpositions. For instance, before auf Grund (von) 双n the basis of' can ever get grammaticalized to a grammatical preposition, it must first be lexicalized to the lexical sign is lexicalized if it is withdrawn from analytic access and inventorized. On the other hand, for a sign to be grammaticalized means for it to acquire functions in the analytic formation of more comprehensive signs. Both processes regularly, but not necessarily involve a reductive component. Consequently, grammaticalization is not the mirror image of lexicalization.

　　Thus, lexicalization and grammaticalization are processes that have much in common and are, to a certain extent, parallel. The mirror image of grammaticalization is degrammaticalization, and the mirror image of lexicalization is folk etymology.