of semantic content. More specifically, with reference to grammaticalization, bleaching refers to the loss of all (or most) lexical content of an entity while only its grammatical content is retained, for example James Matisoff described bleaching as "the partial effacement of a morpheme's semantic features, the stripping away of some of its precise content so it can be used in an abstracter, grammatical-hardware-like way". John Haiman wrote that "semantic reduction, or bleaching, occurs as a morpheme loses its intention: From describing a narrow set of ideas, it comes to describe an ever broader range of them, and eventually may lose its meaning altogether". He saw this as one of the two kinds of change that are always associated with grammaticalization (the other being phonetic reduction). Morphological reduction Once a linguistic expression has changed from a lexical to a grammatical meaning (bleaching), it is likely to lose morphological and syntactic elements that were characteristic of its initial category, but which are not relevant to the grammatical function. This is called decategorialization, or morphological reduction. For example, the demonstrative 'that' as in "that book" came to be used as a relative clause marker, and lost the grammatical category of number ('that' singular vs. 'those' plural), as in "the book that I know" versus "the things that I know". Phonetic erosion Phonetic erosion (also called phonological attrition or phonological reduction), is another process that is often linked to grammaticalization. It implies that a linguistic expression loses phonetic substance when it has undergone grammaticalization. Heine writes that "once a lexeme is conventionalized as a grammatical marker, it tends to undergo erosion; that is, the phonological substance is likely to be reduced in some way and to become more dependent on surrounding phonetic material". Bernd Heine and Tania Kuteva have described different kinds of phonetic erosion for applicable cases: Loss of phonetic segments, including loss of full syllables. Loss of suprasegmental properties, such as stress, tone, or intonation. Loss of phonetic autonomy and adaptation to adjacent phonetic units. Phonetic simplification 'Going to' → 'gonna' (or even 'I am going to' → 'I'm gonna' → 'I'mma') and 'because' → 'coz' are examples of erosion in English. Some linguists trace erosion to the speaker's tendency to follow the principle of least effort, while others think that erosion is a sign of changes taking place. However, phonetic erosion, a common process of language change that can take place